The Oracle VirtualBox Extension Pack is an optional, separately licensed, installation package that includes these additional features:

• VirtualBox Remote Desktop Protocol (VRDP) server. See Remote Display (VRDP Support). This allows remote clients to connect to a VM using RDP. For example in the case of a server running several applications in different VMs. There is no need for a GUI for any of these on the host machine, but you may wish to connect to them remotely for troubleshooting or maintenance.

• Host webcam passthrough. See Webcam Passthrough.

• Intel PXE boot ROM.

• Disk image encryption with AES algorithm. See Encryption of Disk Images.

• Cloud integration features. See Integrating with Oracle Cloud Infrastructure.

Portability

Oracle VirtualBox is available on multiple host platforms, and the same file and image formats are used on each. This enables you to run virtual machines created on one host on another host with a different host OS. For example, you can create a virtual machine (VM) on Windows and then run it on Linux.

In addition, VMs can easily be imported and exported using the Open Virtualization Format (OVF), an industry standard created for this purpose. You can even import OVFs that were created with a different virtualization software. See Importing and Exporting Virtual Machines.

OCI Integration

You can export and import VMs to and from Oracle Cloud Infrastructure. This simplifies development of applications and deployment to the production environment. See Exporting an Appliance to Oracle Cloud Infrastructure.

Guest Additions

The Oracle VirtualBox Guest Additions are software packages that can be installed on VMs to improve their performance and to provide additional integration and communication with the host system. VMs running Guest Additions support automatic adjustment of video resolutions, seamless windows, accelerated 3D graphics, shared folders, clipboard sharing, drag and drop, and more.

Virtual Hardware

Oracle VirtualBox implements virtual hardware devices and drivers, and implements resource sharing with the real hardware on the host.

• Guest multiprocessing (SMP). Oracle VirtualBox can present up to 32 virtual CPUs to each virtual machine, irrespective of how many CPU cores are physically present on your host.

• USB devices. Oracle VirtualBox implements a virtual USB controller and enables you to connect arbitrary USB devices to your virtual machines without having to install device-specific drivers on the host. USB support is not limited to certain device categories. See USB Settings.

• Hardware compatibility. Oracle VirtualBox virtualizes a vast array of virtual devices, among them many devices that are typically provided by other virtualization platforms. That includes IDE, SCSI, and SATA hard disk controllers, several virtual network cards and sound cards, virtual serial ports and an Input/Output Advanced Programmable Interrupt Controller (I/O APIC), which is found in many computer systems. This enables easy cloning of disk images from real machines and importing of third-party virtual machines into Oracle VirtualBox.

• ACPI. The Advanced Configuration and Power Interface (ACPI) is available in Oracle VirtualBox. This enables easy cloning of disk images from real machines or third-party virtual machines into Oracle VirtualBox. With its unique ACPI power status support, Oracle VirtualBox can even report to ACPI-aware guest OSs the power status of the host. For mobile systems running on battery, the guest can thus enable energy saving and notify the user of the remaining power, for example in full screen modes.

• Multiscreen resolutions. Oracle VirtualBox VMs support screen resolutions many times that of a physical screen, allowing them to be spread over a large number of screens attached to the host system.

• Built-in iSCSI support. This unique feature enables you to connect a virtual machine directly to an iSCSI storage server without going through the host system. The VM accesses the iSCSI target directly without the extra overhead that is required for virtualizing hard disks in container files. See iSCSI Servers.

• PXE Network boot. The integrated virtual network cards of Oracle VirtualBox fully support remote booting using the Preboot Execution Environment (PXE).

VM Management

• Multigeneration branched snapshots. Oracle VirtualBox can save arbitrary snapshots of the state of the VM. You can go back in time and revert the VM to any such snapshot and start an alternative VM configuration from there, effectively creating a whole snapshot tree. This can be useful for experimenting with a computing environment, testing, or troubleshooting without the need for frequent backups and restores. See Snapshots. You can create and delete snapshots while the VM is running.

• VM groups. Oracle VirtualBox provides a groups feature that enables the user to organize and control virtual machines collectively, as well as individually. In addition to basic groups, it is also possible for any VM to be in more than one group, and for groups to be nested in a hierarchy. This means you can have groups of groups. In general, the operations that can be performed on groups are the same as those that can be applied to individual VMs: Start, Pause, Reset, Close (Save state, Send Shutdown, Power off), Discard Saved State, Show in File System, Sort.

Remote Access

The VirtualBox Remote Desktop Extension (VRDE) is a host extension package that enables high-performance remote access to any running VM. This extension supports the Remote Desktop Protocol (RDP) originally built into Windows, with special additions for full client USB support.

The VRDE does not rely on the Windows RDP server and therefore works with guest OSs other than Windows, even in text mode, and does not require application support in the VM. The VRDE is described in detail in Remote Display (VRDP Support).

• Oracle VirtualBox also provides

  • Extensible RDP authentication. Oracle VirtualBox already supports Winlogon on Windows and PAM on Linux and Oracle Solaris for RDP authentication. In addition, it includes an easy-to-use SDK which enables you to create arbitrary interfaces for other methods of authentication. See RDP Authentication.

  • USB over RDP. Using RDP virtual channel support, Oracle VirtualBox also enables you to connect arbitrary USB devices locally to a virtual machine which is running remotely on an Oracle VirtualBox RDP server. See Remote USB.

Modular Design and Interfaces

Oracle VirtualBox has an extremely modular design with well-defined internal programming interfaces and a clean separation of client and server code. This makes it easy to control it from several interfaces at once. For example, you can start a VM simply by clicking on a button in the Oracle VirtualBox graphical user interface and then control that machine from the command line, or even remotely.

Oracle VirtualBox also provides a comprehensive software development kit (SDK), that enables integration of Oracle VirtualBox with other software systems. See Oracle VirtualBox Programming Interfaces.

Experimental Features

Features listed as Experimental Features do not qualify for Oracle support. Feedback and suggestions about these features are welcome.

The following table shows the Guest OSs that run on hosts with an x86_64 processor and the tier of Oracle support offered for each. See also Guest OSs That Run on Arm64 Hosts.

The following table shows the Guest OSs that run on hosts with an aarch64 processor and the tier of Oracle support offered for each. See also Guest OSs That Run on x86_64 Hosts.

If you use the Create VM process in VirtualBox Manager, Oracle VirtualBox automatically uses the correct settings for each selected 64-bit OS type. See Creating a New Virtual Machine.

The following limitations apply when using an Arm platform host:

• Using Oracle VirtualBox on an Arm processor running Windows 11 is not covered by Oracle Premier Support. See Windows on Arm Hosts.

• Virtual machines must use an Arm-based guest operating system. Running an x86-based guest operating system on an Arm host platform is not supported.

• Only VMSVGA is supported as a graphics controller.

• Unattended installation isn't available.

• The following System page settings aren't available for Arm guests:

  • Motherboard tab: Chipset, TPM

  • Processor tab: Extended Features such as Enable PAE/NX, Enable Nested VT-x/AMD-V

For the various versions of Windows that are supported as host operating systems, please refer to Choosing an Installation Package.

In addition, Windows Installer must be present on your system. This should be the case for all supported Windows platforms.

The installation directory on Windows hosts must meet certain security requirements, in order to be accepted by the Windows installer.

This also applies for upgrades of Oracle VirtualBox.

        Users               S-1-5-32-545:(OI)(CI)(RX)
        Users               S-1-5-32-545:(DE,WD,AD,WEA,WA)
        Authenticated Users S-1-5-11:(OI)(CI)(RX)
        Authenticated Users S-1-5-11:(DE,WD,AD,WEA,WA)
      

      icacls <Directory> /reset /t /c
      icacls <Directory> /inheritance:d /t /c
      icacls <Directory> /grant *S-1-5-32-545:(OI)(CI)(RX)
      icacls <Directory> /deny  *S-1-5-32-545:(DE,WD,AD,WEA,WA)
      icacls <Directory> /grant *S-1-5-11:(OI)(CI)(RX)
      icacls <Directory> /deny  *S-1-5-11:(DE,WD,AD,WEA,WA)
      

The Oracle VirtualBox installation can be started in either of the following ways:

• By double-clicking on the executable file.

• By entering the following command:

  VirtualBox-<version>-<revision>-Win.exe -extract

  This will extract the installer into a temporary directory, along with the .MSI file. Run the following command to perform the installation:

  msiexec /i VirtualBox-<version>-<revision>-Win.msi

Using either way displays the installation Welcome dialog and enables you to choose where to install Oracle VirtualBox, and which components to install. In addition to the Oracle VirtualBox application, the following components are available:

• USB support. This package contains special drivers for your Windows host that Oracle VirtualBox requires to fully support USB devices inside your virtual machines.

• Networking. This package contains extra networking drivers for your Windows host that Oracle VirtualBox needs to support Bridged Networking. This enables your VM's virtual network cards to be accessed from other machines on your physical network.

• Python support. This package contains Python scripting support for the Oracle VirtualBox API, see Oracle VirtualBox Programming Interfaces. For this to work, an already working Windows Python installation on the system is required.

  See, for example: http://www.python.org/download/windows/.

  Note:

  Python version 3 is required. Python version 2.x is no longer supported.

Depending on your Windows configuration, you may see warnings about unsigned drivers, or similar. Click Continue for these warnings, as otherwise Oracle VirtualBox might not function correctly after installation.

The installer will create an Oracle VirtualBox group in the Windows Start menu, which enables you to launch the application and access its documentation.

With standard settings, Oracle VirtualBox will be installed for all users on the local system. If this is not wanted, you must invoke the installer by first extracting as follows:

VirtualBox.exe -extract

Then, run either of the following commands on the extracted .MSI file. This will install Oracle VirtualBox only for the current user.

VirtualBox.exe -msiparams ALLUSERS=2

msiexec /i VirtualBox-<version>-Win.msi ALLUSERS=2

If you do not want to install all features of Oracle VirtualBox, you can set the optional ADDLOCAL parameter to explicitly name the features to be installed. The following features are available:

VBoxApplication

Main binaries of Oracle VirtualBox.

Note:

This feature must not be absent, since it contains the minimum set of files to have working Oracle VirtualBox installation.

VBoxUSB

USB support.

VBoxNetwork

All networking support. This includes the VBoxNetworkFlt and VBoxNetworkAdp features.

VBoxNetworkFlt

Bridged networking support.

VBoxNetworkAdp

Host-only networking support

VBoxPython

Python support

For example, to only install USB support along with the main binaries, run either of the following commands:

VirtualBox.exe -msiparams ADDLOCAL=VBoxApplication,VBoxUSB

msiexec /i VirtualBox-<version>-Win.msi ADDLOCAL=VBoxApplication,VBoxUSB

Public properties can be specified with the MSI API, to control additional behavior and features of the Windows host installer. Use either of the following commands:

VirtualBox.exe -msiparams NAME=VALUE [...]

msiexec /i VirtualBox-<version>-Win.msi NAME=VALUE [...]

The following public properties are available.

• VBOX_INSTALLDESKTOPSHORTCUT

  Specifies whether or not an Oracle VirtualBox icon on the desktop should be created.

  Set to 1 to enable, 0 to disable. Default is 1.

• VBOX_INSTALLQUICKLAUNCHSHORTCUT

  Specifies whether or not an Oracle VirtualBox icon in the Quick Launch Bar should be created.

  Set to 1 to enable, 0 to disable. Default is 1.

• VBOX_REGISTERFILEEXTENSIONS

  Specifies whether or not the file extensions .vbox, .vbox-extpack, .ovf, .ova, .vdi, .vmdk, .vhd and .vdd should be associated with Oracle VirtualBox. Files of these types then will be opened with Oracle VirtualBox.

  Set to 1 to enable, 0 to disable. Default is 1.

• VBOX_START

  Specifies whether to start Oracle VirtualBox right after successful installation.

  Set to 1 to enable, 0 to disable. Default is 1.

For macOS hosts, Oracle VirtualBox ships in a dmg disk image file. Perform the following steps to install on a macOS host:

1. Double-click the dmg file, to mount the contents.

2. A window opens, prompting you to double-click the VirtualBox.pkg installer file displayed in that window.

3. This starts the installer, which enables you to select where to install Oracle VirtualBox.

4. An Oracle VirtualBox icon is added to the Applications folder in the Finder.

To perform a noninteractive installation of Oracle VirtualBox you can use the command line version of the installer application.

Mount the dmg disk image file, as described in the installation procedure, or use the following command line:

hdiutil attach /path/to/VirtualBox-xyz.dmg

Open a terminal session and run the following command:

sudo installer -pkg /Volumes/VirtualBox/VirtualBox.pkg -target /Volumes/Macintosh\ HD

For the various versions of Linux that are supported as host operating systems, see Choosing an Installation Package.

You may need to install the following package on your Linux system before starting the installation. Some systems will do this for you automatically when you install Oracle VirtualBox.

• Qt 6.5.3 or later.

In order to run other operating systems in virtual machines alongside your main operating system, Oracle VirtualBox needs to integrate very tightly with your system. To do this it installs a driver module called vboxdrv into the system kernel. The kernel is the part of the operating system which controls your processor and physical hardware. Without this kernel module, you can still use VirtualBox Manager to configure virtual machines, but they will not start.

Network drivers called vboxnetflt and vboxnetadp are also installed. They enable virtual machines to make more use of your computer's network capabilities and are needed for any virtual machine networking beyond the basic NAT mode.

Since distributing driver modules separately from the kernel is not something which Linux supports well, the Oracle VirtualBox install process creates the modules on the system where they will be used. This means that you may need to install some software packages from the distribution which are needed for the build process. Required packages may include the following:

• GNU compiler (GCC)

• GNU Make (make)

• Kernel header files

Also ensure that all system updates have been installed and that your system is running the most up-to-date kernel for the distribution.

The following list includes some details of the required files for some common distributions. Start by finding the version name of your kernel, using the command uname -r in a terminal. The list assumes that you have not changed too much from the original installation, in particular that you have not installed a different kernel type.

• With Debian and Ubuntu-based distributions, you must install the correct version of the linux-headers, usually whichever of linux-headers-generic, linux-headers-amd64, linux-headers-i686 or linux-headers-i686-pae best matches the kernel version name. Also, the linux-kbuild package if it exists. Basic Ubuntu releases should have the correct packages installed by default.

• On Fedora, Red Hat, Oracle Linux and many other RPM-based systems, the kernel version sometimes has a code of letters or a word close to the end of the version name. For example "uek" for the Oracle Unbreakable Enterprise Kernel or "default" or "desktop" for the standard kernels. In this case, the package name is kernel-uek-devel or equivalent. If there is no such code, it is usually kernel-devel.

• On some SUSE and openSUSE Linux versions, you may need to install the kernel-source and kernel-syms packages.

If you suspect that something has gone wrong with module installation, check that your system is set up as described above and try running the following command, as root:

rcvboxdrv setup

Kernel Modules and UEFI Secure Boot

Installing Oracle VirtualBox from a Debian or Ubuntu Package

sudo dpkg -i virtualbox-version-number_Ubuntu_xenial_amd64.deb

sudo rcvboxdrv setup

Using the Alternative Generic Installer (VirtualBox.run)

sudo ./VirtualBox.run install

./VirtualBox.run install

sudo usermod -a -G vboxusers username

Performing a Manual Installation

./VirtualBox.run --keep --noexec

sudo mkdir /opt/VirtualBox
sudo tar jxf ./install/VirtualBox.tar.bz2 -C /opt/VirtualBox

mkdir /opt/VirtualBox
tar jxf ./install/VirtualBox.tar.bz2 -C /opt/VirtualBox

make

sudo make install

make install

cp /opt/VirtualBox/vboxdrv.sh /sbin/rcvboxdrv

mkdir /etc/vbox
echo INSTALL_DIR=/opt/VirtualBox > /etc/vbox/vbox.cfg

ln -sf /opt/VirtualBox/VBox.sh /usr/bin/VirtualBox
ln -sf /opt/VirtualBox/VBox.sh /usr/bin/VBoxManage
ln -sf /opt/VirtualBox/VBox.sh /usr/bin/VBoxHeadless

Updating and Uninstalling Oracle VirtualBox

sudo ./VirtualBox.run uninstall

./VirtualBox.run uninstall

/opt/VirtualBox/uninstall.sh

Automatic Installation of Debian Packages

virtualbox virtualbox/module-compilation-allowed boolean true
virtualbox virtualbox/delete-old-modules boolean true

debconf-set-selections vboxconf

Automatic Installation of RPM Packages

The RPM format does not provide a configuration system comparable to the debconf system. See Automatic Installation Options for how to set some common installation options provided by Oracle VirtualBox.

Automatic Installation Options

INSTALL_NO_UDEV=1

INSTALL_NO_GROUP=1

INSTALL_NO_VBOXDRV=1

The Linux installers create the system user group vboxusers during installation. Any system user who is going to use USB devices from Oracle VirtualBox guests must be a member of that group. A user can be made a member of the group vboxusers either by using the desktop user and group tools, or with the following command:

sudo usermod -a -G vboxusers username

The easiest way to start an Oracle VirtualBox program is by running the program of your choice (VirtualBox, VBoxManage, or VBoxHeadless) from a terminal. These are symbolic links to VBox.sh that start the required program for you.

The following detailed instructions should only be of interest if you want to execute Oracle VirtualBox without installing it first. You should start by compiling the vboxdrv kernel module and inserting it into the Linux kernel. Oracle VirtualBox consists of a service daemon, VBoxSVC, and several application programs. The daemon is automatically started if necessary. All Oracle VirtualBox applications will communicate with the daemon through UNIX local domain sockets. There can be multiple daemon instances under different user accounts and applications can only communicate with the daemon running under the user account as the application. The local domain socket resides in a subdirectory of your system's directory for temporary files called .vbox-<username>-ipc. In case of communication problems or server startup problems, you may try to remove this directory.

All Oracle VirtualBox applications (VirtualBox, VBoxManage, and VBoxHeadless) require the Oracle VirtualBox directory to be in the library path, as follows:

LD_LIBRARY_PATH=. ./VBoxManage showvminfo "Windows XP"

Oracle VirtualBox is available as a standard Oracle Solaris package. Download the Oracle VirtualBox SunOS package, which includes the 64-bit version of Oracle VirtualBox. The installation must be performed as root and from the global zone. This is because the Oracle VirtualBox installer loads kernel drivers, which cannot be done from non-global zones. To verify which zone you are currently in, execute the zonename command.

To start installation, run the following commands:

gunzip -cd VirtualBox-version-number-SunOS.tar.gz | tar xvf -

The Oracle VirtualBox kernel package is integrated into the main package. Install the Oracle VirtualBox package as follows:

pkgadd -d VirtualBox-version-number-SunOS.pkg

The installer will then prompt you to enter the package you want to install. Choose 1 or all and proceed. Next the installer will ask you if you want to allow the postinstall script to be executed. Choose y and proceed, as it is essential to execute this script which installs the Oracle VirtualBox kernel module. Following this confirmation the installer will install Oracle VirtualBox and execute the postinstall setup script.

Once the postinstall script has been executed your installation is now complete. You may now safely delete the uncompressed package and autoresponse files from your system. Oracle VirtualBox is installed in /opt/VirtualBox.

The installer creates the system user group vboxuser during installation for Oracle Solaris hosts that support the USB features required by Oracle VirtualBox. Any system user who is going to use USB devices from Oracle VirtualBox guests must be a member of this group. A user can be made a member of this group either by using the desktop user and group tools or by running the following command as root:

usermod -G vboxuser username

Note that adding an active user to the vboxuser group will require the user to log out and then log in again. This should be done manually after successful installation of the package.

The easiest way to start an Oracle VirtualBox program is by running the program of your choice (VirtualBox, VBoxManage, or VBoxHeadless) from a terminal. These are symbolic links to VBox.sh that start the required program for you.

Alternatively, you can directly invoke the required programs from /opt/VirtualBox. Using the links provided is easier as you do not have to enter the full path.

You can configure some elements of the VirtualBox Qt GUI, such as fonts and colours, by running VBoxQtconfig from the terminal.

Uninstallation of Oracle VirtualBox on Oracle Solaris requires root permissions. To perform the uninstallation, start a root terminal session and run the following command:

pkgrm SUNWvbox

After confirmation, this will remove Oracle VirtualBox from your system.

To perform a noninteractive installation of Oracle VirtualBox there is a response file named autoresponse. The installer uses this for responses to inputs, rather than prompting the user.

Extract the tar.gz package as described in Performing the Installation. Then open a root terminal session and run the following command:

pkgadd -d VirtualBox-version-number-SunOS-x86 -n -a autoresponse SUNWvbox

To perform a noninteractive uninstallation, open a root terminal session and run the following command:

pkgrm -n -a /opt/VirtualBox/autoresponse SUNWvbox

After installing Oracle VirtualBox in the global zone (see Installing on Oracle Solaris Hosts for the installation instructions) the first step required to run Oracle VirtualBox in a non-global zone is to modify the zone's configuration to be able to access the Oracle VirtualBox device nodes located in the global zone. This is done by performing the following steps as a zone administrator in the global zone.

global$ zonecfg -z vboxzone
                  

Replace vboxzone with the name of the non-gloabl zone where you plan to run Oracle VirtualBox.

Use zonecfg(8) to add the device resource and the match property for each Oracle VirtualBox device node in the global zone to the non-global zone as follows:

zonecfg:vboxzone> add device
zonecfg:vboxzone:device> set match=/dev/vboxdrv
zonecfg:vboxzone:device> end
zonecfg:vboxzone> add device
zonecfg:vboxzone:device> set match=/dev/vboxdrvu
zonecfg:vboxzone:device> end
zonecfg:vboxzone> exit

On Oracle Solaris 11 if you plan to use VMs configured to use a USB device, e.g. a USB pointing device or a USB pass-through device, you should also pass through the /dev/vboxusbmon device using the steps above.

Oracle Solaris 11 does not support sparse root zones so you will need to loopback mount /opt/VirtualBox from the global zone into the non-global zone at the same path. This is done using zonecfg(8) to set the dir attribute and the special attribute for this directory. For example:

zonecfg:vboxzone> add fs
zonecfg:vboxzone:fs> set dir=/opt/VirtualBox
zonecfg:vboxzone:fs> set special=/opt/VirtualBox
zonecfg:vboxzone:fs> set type=lofs
zonecfg:vboxzone:fs> add options [readonly]
zonecfg:vboxzone:fs> end
zonecfg:vboxzone> exit

After making the above changes using zonecfg(8), reboot the zone using zoneadm(8) as follows:

global$ zoneadm -z vboxzone reboot
                  

for the changes to take effect. You will then be able to run Oracle VirtualBox from /opt/VirtualBox within the configured non-global zone.

1. Download the latest Oracle VirtualBox Extension Pack from Download VirtualBox and save it on the host machine.

2. In VirtualBox Manager, Click Extensions.

3. Click Install and select the extension package file. Follow the on-screen instructions.

   The extension pack is installed on the host and displayed in the extensions list.

Alternatively, in VBoxManage, use extpack install to install the extension pack.

1. In VirtualBox Manager, Click Extensions.

2. Click Oracle VirtualBox Extension Pack, and then click Uninstall.

   The extension pack is uninstalled from the host.

Alternatively, in VBoxManage, use extpack uninstall to remove the extension pack.

Note:

Settings will differ, depending on your host OS.

Selecting the Experience Level

1. In the File menu, choose Preferences.

2. Click Basic or Expert to select the required experience level.

   The number of available settings and tools changes depending on the selected experience level.

When you start a VM for the first time the Unattended Installation process is started automatically, using the ISO image file specified. See Creating a New Virtual Machine.

Follow the onscreen instructions to install your OS.

The installation operation changes the boot device order to boot the virtual hard disk first and then the virtual DVD drive. If the virtual hard disk is empty prior to the automatic installation, the VM boots from the virtual DVD drive and begins the installation.

If the virtual hard disk contains a bootable OS, the installation operation exits. In this case, change the boot device order manually by pressing F12 during the BIOS splash screen.

A status bar is displayed at the bottom of the virtual machine window. The status bar contains icons that enable you to view and change settings for the virtual machine, as follows:

• Highlight an icon to show details of the current settings.

• Right-click an icon to change a setting.

  Some settings, such as audio, can be changed directly by right-clicking the status bar icon. For other settings, you select from the displayed menu options.

Table 4 describes the icons on the status bar.

Oracle VirtualBox provides a virtual USB tablet device to new virtual machines through which mouse events are communicated to the guest OS. If you are running a modern guest OS that can handle such devices, mouse support may work out of the box without the mouse being captured as described below. See Motherboard Tab.

Otherwise, if the virtual machine detects only standard PS/2 mouse and keyboard devices, since the OS in the virtual machine does not know that it is not running on a real computer, it expects to have exclusive control over your keyboard and mouse. But unless you are running the VM in full screen mode, your VM needs to share keyboard and mouse with other applications and possibly other VMs on your host.

After installing a guest OS and before you install the Guest Additions, described in Guest Additions, either your VM or the rest of your computer can own the keyboard and the mouse. Both cannot own the keyboard and mouse at the same time. You will see a second mouse pointer which is always confined to the limits of the VM window. You activate the VM by clicking inside it.

To return ownership of keyboard and mouse to your host OS, Oracle VirtualBox reserves a special key on your keyboard: the Host key. By default, this is the right Ctrl key on your keyboard. On a Mac host, the default Host key is the left Command key. You can change this default using the Preferences window. See Set Oracle VirtualBox Preferences. The current setting for the Host key is always displayed at the bottom right of your VM window.

Figure 1. Host Key Setting on the Virtual Machine Status Bar

This means the following:

• Your keyboard is owned by the VM if the VM window on your host desktop has the keyboard focus. If you have many windows open in your guest OS, the window that has the focus in your VM is used. This means that if you want to enter text within your VM, click the title bar of your VM window first.

  To release keyboard ownership, press the Host key. As explained above, this is typically the right Ctrl key.

  Note that while the VM owns the keyboard, some key sequences, such as Alt+Tab, will no longer be seen by the host, but will go to the guest instead. After you press the Host key to reenable the host keyboard, all key presses will go through the host again, so that sequences such as Alt+Tab will no longer reach the guest. For technical reasons it may not be possible for the VM to get all keyboard input even when it does own the keyboard. Examples of this are the Ctrl+Alt+Del sequence on Windows hosts or single keys grabbed by other applications on X11 hosts such as the GNOME desktop Locate Pointer feature.

• Your mouse is owned by the VM only after you have clicked in the VM window. The host mouse pointer will disappear, and your mouse will drive the guest's pointer instead of your normal mouse pointer.

  Note that mouse ownership is independent of that of the keyboard. Even after you have clicked on a titlebar to be able to enter text into the VM window, your mouse is not necessarily owned by the VM yet.

  To release ownership of your mouse by the VM, press the Host key.

As this behavior is inconvenient, Oracle VirtualBox provides a set of tools and device drivers for guest systems called the Oracle VirtualBox Guest Additions. These tools make VM keyboard and mouse operations much more seamless. Most importantly, the Guest Additions suppress the second "guest" mouse pointer and make your host mouse pointer work directly in the guest. See Guest Additions.

Some OSes expect certain key combinations to initiate certain procedures. The key combinations that you type into a VM might target the host OS, the Oracle VirtualBox software, or the guest OS. The recipient of these keypresses depends on a number of factors, including the key combination itself.

• Host OSes reserve certain key combinations for themselves. For example, you cannot use the Ctrl+Alt+Delete combination to reboot the guest OS in your VM, because this key combination is reserved by the host OS. Even though both Windows and Linux OSes can intercept this key combination, the host OS is rebooted automatically.

  On Linux and Oracle Solaris hosts, which use the X Window System, the key combination Ctrl+Alt+Backspace normally resets the X server and restarts the entire graphical user interface. As the X server intercepts this combination, pressing it will usually restart your host graphical user interface and kill all running programs, including Oracle VirtualBox, in the process.

  On Linux hosts supporting virtual terminals, the key combination Ctrl+Alt+Fx, where Fx is one of the function keys from F1 to F12, normally enables you to switch between virtual terminals. As with Ctrl+Alt+Delete, these combinations are intercepted by the host OS and therefore always switch terminals on the host.

  If, instead, you want to send these key combinations to the guest OS in the virtual machine, you will need to use one of the following methods:

  • Use the items in the Input, Keyboard menu of the virtual machine window. This menu includes the settings Insert Ctrl+Alt+Delete and Insert Ctrl+Alt+Backspace. However, the latter setting affects only Linux guests or Oracle Solaris guests.

    This menu also includes an option for inserting the Host key combination.

  • Use special key combinations with the Host key, which is normally the right Control key. Oracle VirtualBox then translates the following key combinations for the VM:

    • Host key + Del sends Ctrl+Alt+Del to reboot the guest OS.

    • Host key + Backspace sends Ctrl+Alt+Backspace to restart the graphical user interface of a Linux or Oracle Solaris guest.

    • Host key + Function key. For example, use this key combination to simulate Ctrl+Alt+Fx to switch between virtual terminals in a Linux guest.

• For some other keyboard combinations such as Alt+Tab to switch between open windows, Oracle VirtualBox enables you to configure whether these combinations will affect the host or the guest, if a virtual machine currently has the focus. This is a global setting for all virtual machines and can be found under File, Preferences, Input.

• A soft keyboard can be used to input key combinations in the guest. See Using the Soft Keyboard.

Oracle VirtualBox provides a soft keyboard that enables you to input keyboard characters on the guest. A soft keyboard is an on-screen keyboard that can be used as an alternative to a physical keyboard. See Using the Soft Keyboard for details of how to use the soft keyboard.

CAUTION:

For best results, ensure that the keyboard layout configured on the guest OS matches the keyboard layout used by the soft keyboard. Oracle VirtualBox does not do this automatically.

The soft keyboard can be used in the following scenarios:

• When the physical keyboard on the host is not the same as the keyboard layout configured on the guest. For example, if the guest is configured to use an international keyboard, but the host keyboard is US English.

• To send special key combinations to the guest. Note that some common key combinations are also available in the Input, Keyboard menu of the guest VM window. See Typing Special Characters.

• For guests in kiosk mode, where a physical keyboard is not present.

• When using nested virtualization, the soft keyboard provides a method of sending key presses to a guest.

By default, the soft keyboard includes some common international keyboard layouts. You can copy and modify these to meet your own requirements. See Creating a Custom Keyboard Layout.

Using the Soft Keyboard

Creating a Custom Keyboard Layout

You can resize the VM's window while that VM is running. When you do, the window is scaled as follows:

• If you have scaled mode enabled, then the virtual machine's screen will be scaled to the size of the window. This can be useful if you have many machines running and want to have a look at one of them while it is running in the background. Alternatively, it might be useful to enlarge a window if the VM's output screen is very small, for example because you are running an old OS in it.

  To enable scaled mode, press Host key + C, or select Scaled Mode from the View menu in the VM window. To leave scaled mode, press Host key + C again.

  The aspect ratio of the guest screen is preserved when resizing the window. To ignore the aspect ratio, press Shift during the resize operation.

• If you have the Guest Additions installed and they support automatic resizing, the Guest Additions will automatically adjust the screen resolution of the guest OS. For example, if you are running a Windows guest with a resolution of 1024x768 pixels and you then resize the VM window to make it 100 pixels wider, the Guest Additions will change the Windows display resolution to 1124x768.

  See Guest Additions.

• Otherwise, if the window is bigger than the VM's screen, the screen will be centered. If it is smaller, then scroll bars will be added to the machine window.

Pausing a VM suspends all the processes running on the VM.

Resetting a VM is the equivalent of choosing the reset or restart option in the OS. It does not reset to factory settings or other known state, it restarts the guest OS.

When you click the Close button of your virtual machine window, at the top right of the window, just like you would close any other window on your system, Oracle VirtualBox asks you whether you want to save or power off the VM. As a shortcut, you can also press Host key + Q.

The difference between the three options is important. They mean the following:

• Save State With this option, Oracle VirtualBox freezes the virtual machine by completely saving its state to your local disk.

  When you start the VM again later, you will find that the VM continues exactly where it was left off. All your programs will still be open, and your computer resumes operation. Saving the state of a virtual machine is thus in some ways similar to suspending a laptop by closing its lid.

• Shut Down This will send an ACPI shutdown signal to the virtual machine, which has the same effect as if you had pressed the power button on a real computer. This should trigger a proper shutdown mechanism from within the VM. State is not saved. Save any open applications before choosing this option.

• Power Off With this option, Oracle VirtualBox also stops running the virtual machine, but immediately without shutdown procedures or saving its state.

  CAUTION:

  This is equivalent to pulling the power plug on a real computer without shutting it down properly. If you start the machine again after powering it off, your OS will have to reboot completely and may begin a lengthy check of its virtual system disks. As a result, this should not normally be done, since it can potentially cause data loss or an inconsistent state of the guest system on disk.

  As an exception, if your virtual machine has any snapshots, see Snapshots, you can use this option to quickly restore the current snapshot of the virtual machine. In that case, powering off the machine will discard the current state and any changes made since the previous snapshot was taken will be lost.

The Discard button discards a virtual machine's saved state. This has the same effect as powering it off, and the same warnings apply.

OVF is a cross-platform standard supported by many virtualization products which enables the creation of ready-made virtual machines that can then be imported into a hypervisor such as Oracle VirtualBox. Oracle VirtualBox makes OVF import and export easy to do, using VirtualBox Manager or the command-line interface.

Using OVF enables packaging of virtual appliances. These are disk images, together with configuration settings that can be distributed easily. This way one can offer complete ready-to-use software packages, including OSes with applications, that need no configuration or installation except for importing into Oracle VirtualBox.

Appliances in OVF format can appear in the following variants:

• They can come in several files, as one or several disk images, typically in the widely-used VMDK format. See Disk Image Files (VDI, VMDK, VHD, HDD). They also include a textual description file in an XML dialect with an .ovf extension. These files must then reside in the same directory for Oracle VirtualBox to be able to import them.

• Alternatively, the above files can be packed together into a single archive file, typically with an .ova extension. Such archive files use a variant of the TAR archive format and can therefore be unpacked outside of Oracle VirtualBox with any utility that can unpack standard TAR files.

The following steps show how to import one or more VMs from OVF format.

1. In VirtualBox Manager, click Home, and then click Import. Choose the file you want to import.

   Alternatively, double-click the OVF or OVA file in your file manager. Oracle VirtualBox creates file type associations automatically for any OVF and OVA files on your host OS.

2. In Appliance Settings, check the VMs described in the OVF or OVA file and change any of the VM settings you need to.

3. By default, membership of VM groups is preserved on import for VMs that were initially exported from Oracle VirtualBox. You can change this behavior by using the Primary Group setting for the VM.

   The following global settings apply to all of the VMs that you import:

   • Base Folder: Specifies the directory on the host in which to store the imported VMs.

     If an appliance has multiple VMs, you can specify a different directory for each VM by editing the Base Folder setting for the VM.

   • MAC Address Policy: Reinitializes the MAC addresses of network cards in your VMs prior to import, by default. You can override the default behavior and preserve the MAC addresses on import.

   • Import Hard Drives as VDI: Imports hard drives in the VDI format rather than in the default VMDK format.

4. Click Finish to import the appliance.

   Oracle VirtualBox copies the disk images and creates local VMs with the settings described on the Appliance Settings page. The imported VMs are shown in the list of VMs in VirtualBox Manager.

   Because disk images are large, the VMDK images that are included with virtual appliances are shipped in a compressed format that cannot be used directly by VMs. So, the images are first unpacked and copied, which might take several minutes.

You can use the VBoxManage import command to import an appliance. See VBoxManage import.

The following steps show how to export one or more VMs to OVF format.

1. Select File, Export Appliance.

   On the initial Virtual machines page, you can combine several VMs into an OVF appliance.

   Select one or more VMs to export, and click Next.

2. The Format Settings page enables you to configure the following settings:

   • Format: Selects the Open Virtualization Format value for the output files.

     The Oracle Cloud Infrastructure value exports the appliance to Oracle Cloud Infrastructure. See Exporting an Appliance to Oracle Cloud Infrastructure.

   • File: Selects the location in which to store the exported files.

   • MAC Address Policy: Specifies whether to retain or reassign network card MAC addresses on export.

   • Write Manifest File: Enables you to include a manifest file in the exported archive file.

   • Include ISO Image Files: Enables you to include ISO image files in the exported archive file.

3. Click Next to show the Appliance Settings page.

   You can edit settings for the virtual appliance. For example, you can change the name of the virtual appliance or add product information, such as vendor details or license text.

   Double-click the appropriate field to change its value.

4. Click Finish to begin the export process. Note that this operation might take several minutes.

You can use the VBoxManage export command to export an appliance. See VBoxManage export.

You may need to change the configuration of a Virtual Machine (VM) after it has been created. For example, you may want to add more memory.

Be careful when changing VM settings. It is possible to change all VM settings after installing a guest OS, but certain changes might prevent a guest OS from functioning correctly if done after installation.

The parameters are described in detail in Virtual Machine Settings.

Even more parameters are available when using the VBoxManage command line interface. See VBoxManage.

Create VM groups if you want to manage several VMs together, and perform functions on them collectively, as well as individually.

• Create a group using VirtualBox Manager. Do one of the following:

  • Drag a VM on top of another VM.

  • Select multiple VMs and choose Move to Group, New Group from the right-click menu.

• A default name is assigned to new groups, following the format New Group <Number>. To rename the new group, right-click on the group's name and choose Rename Group. Type the new name, and then press Enter.

• To remove a VM from a group, right-click the VM and choose Move to Group, No Group.

• Create and manage a group using the command line. Do one of the following:

  • Create a group and assign a VM. For example:

    VBoxManage modifyvm "vm01" --groups "/TestGroup"

    This command creates a group TestGroup and attaches the VM vm01 to that group.

  • Detach a VM from the group, and delete the group if empty. For example:

    VBoxManage modifyvm "vm01" --groups ""

    This command detaches all groups from the VM vm01 and deletes the empty group.

• Create multiple groups. For example:

  VBoxManage modifyvm "vm01" --groups "/TestGroup,/TestGroup2"

  This command creates the groups TestGroup and TestGroup2, if they do not exist, and attaches the VM vm01 to both of them.

• Create nested groups, having a group hierarchy. For example:

  VBoxManage modifyvm "vm01" --groups "/TestGroup/TestGroup2"

  This command attaches the VM vm01 to the subgroup TestGroup2 of the TestGroup group.

• Use VirtualBox Manager menu options to control and manage all the VMs in a group. For example: Start, Pause, Reset, Close (save state, send shutdown signal, poweroff), Discard Saved State, Show in Explorer, Sort.

There are three operations related to snapshots, as follows:

1. Take a snapshot. This makes a copy of the machine's current state, to which you can go back at any given time later.

   • If your VM is running:

     In the VM window, select Take Snapshot from the Machine menu.

     The VM is paused while the snapshot is being created. After snapshot creation, the VM continues to run as normal.

   • In VirtualBox Manager, if your VM is in either the Saved or the Powered Off state, as displayed next to the VM name in the Machines list:

     Click Snapshots and do one of the following:

     • Click Take in the Snapshots toolbar.

     • Right-click the Current State item in the snapshots list and select Take.

   A dialog is displayed, prompting you for a snapshot name. This name is purely for reference purposes, to help you remember the state of the snapshot. For example, a useful name would be Fresh installation from scratch, no Guest Additions, or Service Pack 3 just installed. You can also add a longer text description in the Snapshot Description field.

   Your new snapshot will then appear in the snapshots list. Underneath your new snapshot, you will see an item called Current State, signifying that the current state of your VM is a variation based on the snapshot you took earlier. If you later take another snapshot, you will see that they are displayed in sequence, and that each subsequent snapshot is derived from an earlier one.

   Oracle VirtualBox imposes no limits on the number of snapshots you can take. The only practical limitation is disk space on your host. Each snapshot stores the state of the virtual machine and thus occupies some disk space. See Snapshot Contents for details on what is stored in a snapshot.

2. Restore a snapshot. In the Snapshots tab, select the snapshot you have taken and click Restore in the toolbar. By restoring a snapshot, you go back or forward in time. The current state of the machine is lost, and the machine is restored to the exact state it was in when the snapshot was taken.

   Note:

   Restoring a snapshot will affect the virtual hard drives that are connected to your VM, as the entire state of the virtual hard drive will be reverted as well. This means also that all files that have been created since the snapshot and all other file changes will be lost. In order to prevent such data loss while still making use of the snapshot feature, it is possible to add a second hard drive in write-through mode using the VBoxManage interface and use it to store your data. As write-through hard drives are not included in snapshots, they remain unaltered when a machine is reverted. See Special Image Write Modes.

   To avoid losing the current state when restoring a snapshot, you can create a new snapshot before the restore operation.

   By restoring an earlier snapshot and taking more snapshots from there, it is even possible to create a kind of alternate reality and to switch between these different histories of the virtual machine. This can result in a whole tree of virtual machine snapshots.

3. Delete a snapshot. This does not affect the state of the virtual machine, but only releases the files on disk that Oracle VirtualBox used to store the snapshot data, thus freeing disk space. To delete a snapshot, select the snapshot name in the Snapshots tab and click Delete in the toolbar. Snapshots can be deleted even while a machine is running.

   Note:

   Whereas taking and restoring snapshots are fairly quick operations, deleting a snapshot can take a considerable amount of time since large amounts of data may need to be copied between several disk image files. Temporary disk files may also need large amounts of disk space while the operation is in progress.

   There are some situations that cannot be handled while a VM is running, and you will get an appropriate message that you need to perform this snapshot deletion when the VM is shut down.

Think of a snapshot as a point in time that you have preserved. More formally, a snapshot consists of the following:

• The snapshot contains a complete copy of the VM settings, including the hardware configuration, so that when you restore a snapshot, the VM settings are restored as well. For example, if you changed the hard disk configuration or the VM's system settings, that change is undone when you restore the snapshot.

  The copy of the settings is stored in the machine configuration, an XML text file, and thus occupies very little space.

• The complete state of all the virtual disks attached to the machine is preserved. Going back to a snapshot means that all changes that had been made to the machine's disks, file by file and bit by bit, will be undone. Files that were since created will disappear, files that were deleted will be restored, changes to files will be reverted.

  Strictly speaking, this is only true for virtual hard disks in "normal" mode. You can configure disks to behave differently with snapshots, see Special Image Write Modes. In technical terms, it is not the virtual disk itself that is restored when a snapshot is restored. Instead, when a snapshot is taken, Oracle VirtualBox creates differencing images which contain only the changes since the snapshot were taken. When the snapshot is restored, Oracle VirtualBox throws away that differencing image, thus going back to the previous state. This is both faster and uses less disk space. For the details, which can be complex, see Differencing Images.

  Creating the differencing image as such does not occupy much space on the host disk initially, since the differencing image will initially be empty and grow dynamically later with each write operation to the disk. The longer you use the machine after having created the snapshot, however, the more the differencing image will grow in size.

• If you took a snapshot while the machine was running, the memory state of the machine is also saved in the snapshot. This is in the same way that memory can be saved when you close a VM window. When you restore such a snapshot, execution resumes at exactly the point when the snapshot was taken.

  The memory state file can be as large as the memory size of the VM and will therefore occupy considerable disk space.

Note:

The available settings depend on the selected experience level. To display all available settings, ensure the experience level is set to Expert.

See Experience Levels for VirtualBox Manager.

On the Identity tab of the General settings category, you can find these settings:

• VM Name: The name of the the VM, as shown in the list of VMs in the main VirtualBox Manager window. Using this name, Oracle VirtualBox also saves the VM's configuration files. If you change the name, Oracle VirtualBox renames these files as well. As a result, you can only use characters which are allowed for file names on your host OS.

  Note that internally, Oracle VirtualBox uses unique identifiers (UUIDs) to identify virtual machines. You can display these using the VBoxManage commands.

• OS: The type of guest OS for the VM. Additionally, set the OS Distribution or OS Edition, and OS Version. For example, if the OS is Linux, the OS Distribution might be Oracle Linux and the OS Version might be Oracle Linux 8.x (64-bit).

  These are the same settings that are specified in the New Virtual Machine workflow. See Creating a New Virtual Machine.

  Whereas the default settings of a newly created VM depend on the selected OS, changing the OS later has no effect on VM settings.

The following settings are available in the Features tab:

• Snapshot Folder: By default, Oracle VirtualBox saves snapshot data together with your other Oracle VirtualBox configuration data. See Where Oracle VirtualBox Stores its Files. With this setting, you can specify any other folder for each VM.

• Shared Clipboard: You can select here whether the clipboard of the guest OS should be shared with that of your host. If you select Bidirectional, then Oracle VirtualBox will always make sure that both clipboards contain the same data. If you select Host to Guest or Guest to Host, then Oracle VirtualBox will only ever copy clipboard data in one direction.

  Clipboard sharing requires the Oracle VirtualBox Guest Additions.

  For security reasons, the shared clipboard is disabled by default. This setting can be changed at any time using the Shared Clipboard menu item in the Devices menu of the virtual machine.

• Drag and Drop: You can select multiple drag and drop modes for a VM to enable or restrict access in either direction.

  For drag and drop to work, the Guest Additions need to be installed on the guest.

  Note:

  Drag and drop is disabled by default. This setting can be changed at any time using the Drag and Drop menu item in the Devices menu of the virtual machine.

  See Drag and Drop.

On the Description tab you can enter a description for your virtual machine. This has no effect on the functionality of the machine, but you may find this space useful to note down things such as the configuration of a virtual machine and the software that has been installed into it.

To insert a line break into the Description text field, press Shift+Enter.

The Disk Encryption tab enables you to encrypt disks that are attached to the virtual machine.

To enable disk encryption, select the Encrypt Disks check box.

Settings are available to configure the cipher used for encryption and the encryption password.

Note:

As the activation mechanism of Windows is sensitive to hardware changes, if you are changing hardware settings for a Windows guest, some of these changes may trigger a request for another activation with Microsoft.

On the Motherboard tab, you can configure virtual hardware that would normally be on the motherboard of a real computer.

• Base Memory: Sets the amount of RAM that is allocated and given to the VM when it is running. The specified amount of memory will be requested from the host OS, so it must be available or made available as free memory on the host when attempting to start the VM and will not be available to the host while the VM is running. This is the same setting that was specified when Creating a New Virtual Machine.

  Generally, it is possible to change the memory size after installing the guest OS. But you must not reduce the memory to an amount where the OS would no longer boot.

• Boot Device Order (BIOS only): Determines the order in which the guest OS will attempt to boot from the various virtual boot devices. Analogous to a real PC's BIOS setting, Oracle VirtualBox can tell a guest OS to start from the virtual floppy, the virtual CD/DVD drive, the virtual hard drive (each of these as defined by the other VM settings), the network, or none of these.

  If you select Network, the VM will attempt to boot from a network using the PXE mechanism. This needs to be configured in detail on the command line. See VBoxManage modifyvm.

• Chipset: You can select which chipset will be presented to the virtual machine. This can't be changed on VMs with an Arm architecture. PIIX3 is the default chipset for most guests. For some guest OSs, the PIIX3 chipset is not well supported. As a result, Oracle VirtualBox provides an emulation of the ICH9 chipset, which supports PCI express, three PCI buses, PCI-to-PCI bridges and Message Signaled Interrupts (MSI). This enables modern OSs to address more PCI devices and no longer requires IRQ sharing. Using the ICH9 chipset it is also possible to configure up to 36 network cards, compared to a maximum of eight network adapters with PIIX3.

• TPM Version: Enables support for a Trusted Platform Module (TPM) security processor. Choose from the available TPM versions. This can't be changed on VMs with an Arm architecture.

• Pointing Device: The default virtual pointing device for some guest OSs is the traditional PS/2 mouse. If set to USB Tablet, Oracle VirtualBox reports to the virtual machine that a USB tablet device is present and communicates mouse events to the virtual machine through this device. Another setting is USB Multi-Touch Tablet, which is suitable for guests running Windows 8 or later.

  Using the virtual USB tablet has the advantage that movements are reported in absolute coordinates, instead of as relative position changes. This enables Oracle VirtualBox to translate mouse events over the VM window into tablet events without having to capture the mouse in the guest as described in Capturing and Releasing Keyboard and Mouse. This makes using the VM less tedious even if Guest Additions are not installed.

• I/O APIC: Advanced Programmable Interrupt Controllers (APICs) are an x86 hardware feature that have replaced Programmable Interrupt Controllers (PICs). With an I/O APIC, OSs can use more than 16 interrupt requests (IRQs) and therefore avoid IRQ sharing for improved reliability. Can't be changed on VMs with an Arm architecture.

  Note:

  Enabling the I/O APIC is required for 64-bit Windows guest OSs. It is also required if you want to use more than one virtual CPU in a virtual machine.

  However, software support for I/O APICs has been unreliable with some OSs other than Windows. Also, the use of an I/O APIC slightly increases the overhead of virtualization and therefore slows down the guest OS a little.

  Note:

  All Windows OSs install different kernels, depending on whether an I/O APIC is available. As with ACPI, the I/O APIC therefore must not be turned off after installation of a Windows guest OS. Turning it on after installation will have no effect however.

• Hardware Clock in UTC: If selected, Oracle VirtualBox will report the system time in UTC format to the guest instead of the local (host) time. This affects how the virtual real-time clock (RTC) operates and may be useful for UNIX-like guest OSs, which typically expect the hardware clock to be set to UTC.

• UEFI Enables Extensible Firmware Interface (EFI), which replaces the legacy BIOS and may be useful for certain advanced use cases. See Alternative Firmware (UEFI). Can't be changed on VMs with an Arm architecture.

• Secure Boot: Enables Secure Boot, to provide a secure environment for starting the guest OS.

In addition, you can turn off the Advanced Configuration and Power Interface (ACPI) which Oracle VirtualBox presents to the guest OS by default.

ACPI is the current industry standard to allow OSs to recognize hardware, configure motherboards and other devices and manage power. As most computers contain this feature and Windows and Linux support ACPI, it is also enabled by default in Oracle VirtualBox. However, no ACPI information, such as battery status or power source, is reported to Oracle Solaris guests.

ACPI can only be turned off using the command line. See VBoxManage modifyvm.

On the Processor tab, you can configure settings for the CPU used by the virtual machine.

• Number of CPUs: Sets the number of virtual CPU cores the guest OSes can see. Oracle VirtualBox supports symmetrical multiprocessing (SMP) and can present up to 32 virtual CPU cores to each virtual machine.

  You should not configure virtual machines to use more CPU cores than are available physically. This includes real cores, with no hyperthreads.

• Processing Cap: Configures the CPU processing cap. This limits the amount of time a host CPU spends to emulate a virtual CPU. The default setting is 100%, meaning that there is no limitation. A setting of 50% implies a single virtual CPU can use up to 50% of a single host CPU. Note that limiting the execution time of the virtual CPUs may cause guest timing problems.

  A warning is displayed at the bottom of the Processor tab if a Processing Cap setting is made that may affect system performance.

• PAE/NX: Determines whether the PAE (Physical Address Extension) and NX capabilities of the host CPU will be exposed to the virtual machine. Can't be changed on VMs with an Arm architecture.

  Normally, if enabled and supported by the OS, then even a 32-bit x86 CPU can access more than 4 GB of RAM. This is made possible by adding another 4 bits to memory addresses, so that with 36 bits, up to 64 GB can be addressed. Some OSs, such as Ubuntu Server, require PAE support from the CPU and cannot be run in a virtual machine without it.

• Nested VT-x/AMD-V: Enables nested virtualization, with passthrough of hardware virtualization functions to the guest VM. Can't be changed on VMs with an Arm architecture.

With virtual machines running modern server OSs, Oracle VirtualBox also supports CPU hot-plugging. For details, see CPU Hot-Plugging.

On this tab, you can configure Oracle VirtualBox to use hardware virtualization extensions that your host CPU supports.

• Paravirtualization Interface: Oracle VirtualBox provides paravirtualization interfaces to improve time-keeping accuracy and performance of guest OSs. The options available are documented under the --paravirt-provider option in VBoxManage modifyvm. For further details on the paravirtualization providers, see Paravirtualization Providers.

• Hardware Virtualization:

  • Nested Paging: If the host CPU supports the nested paging (AMD-V) or EPT (Intel VT-x) features, then you can expect a significant performance increase by enabling nested paging in addition to hardware virtualization. For technical details, see Nested Paging and VPIDs. For Intel EPT security recommendations, see CVE-2018-3646.

• Video Memory: Sets the size of the memory provided by the virtual graphics card available to the guest, in megabytes. As with the main memory, the specified amount will be allocated from the host's resident memory. Based on the amount of video memory, higher resolutions and color depths may be available.

  VirtualBox Manager will show a warning if the amount of video memory is too small to be able to switch the VM into full screen mode. The minimum value depends on the number of virtual monitors, the screen resolution and the color depth of the host display as well as on the use of 3D acceleration. A rough estimate is (color depth / 8) x vertical pixels x horizontal pixels x number of screens = number of bytes. Extra memory may be required if display acceleration is used.

• Number of Virtual Monitors: With this setting, Oracle VirtualBox can provide more than one virtual monitor to a virtual machine. If a guest OS supports multiple attached monitors, Oracle VirtualBox can pretend that multiple virtual monitors are present. Up to eight such virtual monitors are supported.

  The output of the multiple monitors are displayed on the host in multiple VM windows which are running side by side. However, in full screen and seamless mode, they use the available physical monitors attached to the host. As a result, for full screen and seamless modes to work with multiple monitors, you will need at least as many physical monitors as you have virtual monitors configured, or Oracle VirtualBox will report an error.

  You can configure the relationship between guest and host monitors using the View menu by pressing Host key + Home when you are in full screen or seamless mode.

  See also Known Issues.

• Scale Factor: Enables scaling of the display size. For multiple monitor displays, you can set the scale factor for individual monitors, or globally for all of the monitors. Use the slider to select a scaling factor up to 200%.

  You can set a default scale factor for all VMs. Use the Display tab in the Preferences window.

• Graphics Controller: Specifies the graphics adapter type used by the guest VM. Note that you must install the Guest Additions on the guest VM to specify the VBoxSVGA or VMSVGA graphics controller. The following options are available:

  • VBoxSVGA: The default graphics controller for new VMs that use Windows 7 or later.

    This graphics controller improves performance and 3D support when compared to the legacy VBoxVGA option.

  • VBoxVGA: Use this graphics controller for legacy guest OSes. This is the default graphics controller for Windows versions before Windows 7 and for Oracle Solaris.

    3D acceleration is not supported for this graphics controller.

  • VMSVGA: Use this graphics controller to emulate a VMware SVGA graphics device. This is the default graphics controller for Linux guests.

  • None: Does not emulate a graphics adapter type.

• 3D Acceleration: If a virtual machine has Guest Additions installed, you can enable accelerated 3D graphics on the VM. With 3D acceleration enabled, the VM also uses video decoding acceleration if the host also supports video decoding acceleration. See Hardware-Accelerated Graphics.

On the Remote Display tab, if the VirtualBox Remote Display Extension (VRDE) is installed, you can enable the VRDP server that is built into Oracle VirtualBox. This enables you to connect to the console of the virtual machine remotely with any standard RDP viewer, such as mstsc.exe that comes with Microsoft Windows. On Linux and Oracle Solaris systems you can use the standard open source rdesktop program. These features are described in Remote Display (VRDP Support).

• Enable Server: Select this check box and configure settings for the remote display connection.

On the Recording tab you can enable video and audio recording for a virtual machine and change related settings. Note that these features can be enabled and disabled while a VM is running. Settings apply to all selected screens.

• Enable Recording: Select this check box and select a Recording Mode option.

• Recording Mode: You can choose to record video, audio, or both video and audio.

  Some settings on the Recording tab may be grayed out, depending on the Recording Mode setting.

• File Path: The file where the recording is saved.

• Frame Size: The video resolution of the recorded video, in pixels. The drop-down list enables you to select from common frame sizes.

• Frame Rate: Use the slider to set the maximum number of video frames per second (FPS) to record. Frames that have a higher frequency are skipped. Increasing this value reduces the number of skipped frames and increases the file size.

• Video Quality: Use the slider to set the bit rate of the video in kilobits per second. Increasing this value improves the appearance of the video at the cost of an increased file size.

• Audio Quality: Use the slider to set the quality of the audio recording. Increasing this value improves the audio quality at the cost of an increased file size.

• Screens: For a multiple monitor display, you can select which screens to record video from.

As you adjust the video and audio recording settings, the approximate output file size for a five minute video is shown.

Note:

This section gives a quick introduction to the Oracle VirtualBox storage settings. See Virtual Storage for a full description of the available storage settings in Oracle VirtualBox.

The USB section in a virtual machine's Settings window enables you to configure Oracle VirtualBox's sophisticated USB support.

Oracle VirtualBox can enable virtual machines to access the USB devices on your host directly. To achieve this, Oracle VirtualBox presents the guest OS with a virtual USB controller.

Oracle VirtualBox also enables your guests to connect to remote USB devices by use of the VirtualBox Remote Desktop Extension (VRDE). See Remote USB.

Enable USB for a VM

1. Ensure the VM is not running.
2. Select the VM in the machine list, and then click Settings.
3. On the USB tab, select Enable USB Controller and choose the USB Controller you need for your guest OS. In most cases this will be xHCI. Only use OHCI or EHCI if your guest OS does not support xHCI. For some legacy Windows guests you'll need to install third party drivers for xHCI support.
   • OHCI supports USB 1.1
   • EHCI supports USB 2.0. This also enables OHCI.
   • xHCI supports all USB speeds up to USB 3.0
4. Specify which devices can be attached to the guest by adding USB Device Filters. USB devices with a matching filter will be automatically passed to the guest once they are attached to the host. USB devices without a matching filter can be passed manually to the guest, for example by using the Devices, USB menu.
   • Click the USB filter button to create a new filter with blank fields, and then complete the fields.
   • Or, click the Add USB filter button to create a filter with the fields completed for the selected USB device.

   Give the filter a name, for later reference, and specify the filter criteria. The more criteria you specify, the more precisely devices will be selected. For instance, if you specify only a vendor ID of 046d, all devices produced by Logitech will be available to the guest. If you fill in all fields, on the other hand, the filter will only apply to a particular device model from a particular vendor, and not even to other devices of the same type with a different revision and serial number.

   The following criteria are available:

   • Vendor and Product ID. With USB, each vendor of USB products carries an identification number that is unique world-wide, called the vendor ID. Similarly, each line of products is assigned a product ID number. Both numbers are commonly written in hexadecimal, and a colon separates the vendor from the product ID. For example, 046d:c016 stands for Logitech as a vendor, and the M-UV69a Optical Wheel Mouse product.

     Alternatively, you can also specify Manufacturer and Product by name.

     To list all the USB devices that are connected to your host machine with their respective vendor IDs and product IDs, use the following command:

     VBoxManage list usbhost

     On Windows, you can also see all USB devices that are attached to your system in the Device Manager. On Linux, you can use the lsusb command.

   • Serial Number. While vendor ID and product ID are quite specific to identify USB devices, if you have two identical devices of the same brand and product line, you will also need their serial numbers to filter them out correctly.

   • Remote. This setting specifies whether the device will be local only, remote only, such as over VRDP, or either.

   As an example, you could create a new USB filter and specify a vendor ID of 046d for Logitech, Inc, a manufacturer index of 1, and not remote. Then any USB devices on the host system produced by Logitech, Inc with a manufacturer index of 1 will be visible to the guest system.

   Several filters can select a single device. For example, a filter which selects all Logitech devices, and one which selects a particular webcam.

5. On a Windows host, you will need to unplug and reconnect a USB device to use it after creating a filter for it.

6. Ensure the filters you need immediately are selected in the list. Selected filters will be attached automatically when the VM starts.

On Windows hosts, a kernel mode device driver provides USB proxy support. It implements both a USB monitor, which enables Oracle VirtualBox to capture devices when they are plugged in, and a USB device driver to claim USB devices for a particular virtual machine. System reboots are not necessary after installing the driver. Also, you do not need to replug devices for Oracle VirtualBox to claim them.

On supported Linux hosts, Oracle VirtualBox accesses USB devices through special files in the file system. When Oracle VirtualBox is installed, these are made available to all users in the vboxusers system group. In order to be able to access USB from guest systems, make sure that you are a member of this group.

EFI provides two distinct video interfaces: GOP (Graphics Output Protocol) and UGA (Universal Graphics Adapter). Modern OSes, such as Mac OS X, generally use GOP, while some older ones still use UGA. Oracle VirtualBox provides a configuration option to control the graphics resolution for both interfaces, making the difference mostly irrelevant for users.

The default resolution is 1024x768. To select a graphics resolution for EFI, use the following VBoxManage command:

VBoxManage setextradata "VM name" VBoxInternal2/EfiGraphicsResolution HxV

If this list of default resolutions does not cover your needs, see Custom VESA Resolutions. Note that the color depth value specified in a custom video mode must be specified. Color depths of 8, 16, 24, and 32 are accepted. EFI assumes a color depth of 32 by default.

The EFI default video resolution settings can only be changed when the VM is powered off.

It is currently not possible to manipulate EFI variables from within a running guest. For example, setting the boot-args variable by running the nvram tool in a Mac OS X guest will not work. As an alternative method, VBoxInternal2/EfiBootArgs extradata can be passed to a VM in order to set the boot-args variable. To change the boot-args EFI variable, use the following command:

VBoxManage setextradata "VM name" VBoxInternal2/EfiBootArgs <value>

Note:

To monitor a cloud VM, the Compute Instance Monitoring plugin must be enabled and running on the Oracle Cloud Infrastructure instance. See the Oracle Cloud Infrastructure documentation for more details.

The Resources tool displays several performance metrics for all running virtual machines and cloud VM instances, and for the host system. This provides an overview of system resources used by individual virtual machines and the host system.

To display the Resources, in VirtualBox Manager click Resources.

• To show metrics for all virtual machines, including those that are not running, right-click the list of virtual machines and select List All Virtual Machines.
• To show metrics for cloud VMs, right-click the list of virtual machines and select Show Cloud Virtual Machines.
• To configure the set of metrics to be shown, click Columns in the toolbar. You can then sort the list of virtual machines by a particular metric.
• To see more performance information for a virtual machine, select the VM name and click Resource Use in the toolbar. The Resource Use tab of the Session Information dialog is shown, see Session Information Dialog.

The Session Information dialog includes multiple tabs that show important configuration and runtime information for the guest system. The tabs are as follows:

• Configuration Details. Displays the system configuration of the virtual machine in a tabular format. The displayed information includes details such as storage configuration and audio settings.

• Runtime Information. Displays runtime information for the guest session in a tabular format similar to the Configuration Details tab.

• Resource Use. Includes several time series charts which monitor guest resource usage including CPU, RAM, Disk I/O, and Network. Note that the RAM chart requires the Guest Additions to be running on the guest system. The Resource Use tab can also be accessed directly from the Resources. See Resources.

• Guest Control. Details of processes used by the Guest Control File Manager. See Guest Control File Manager.

To display session information for a guest VM or a cloud VM, select the VM name in the Machines list and click the Resource Use tab.

Every time you start up a VM, Oracle VirtualBox creates a log file that records system configuration and events. The Log Viewer is a VirtualBox Manager tool that enables you to view and analyze system logs.

To display the Log Viewer, do either of the following:

• Click the VM name in the machine list and select Logs from the machine tools menu.

• In the VM, select Machine, Show Log.

Log messages for the VM are displayed in tabs in the Log Viewer window. See Collecting Debugging Information for details of the various log files generated by Oracle VirtualBox.

If you select multiple VMs in the machine list, logs are listed for each VM.

The toolbar of the Log Viewer includes the following options:

• Save: Exports the contents of the selected log file to a text file. Specify the destination filename and location in the displayed dialog.

• Find: Searches for a text string in the log file.

• Filter: Uses filter terms to display specific types of log messages. Common log message terms used by Oracle VirtualBox, such as Audio and NAT, are included by default. Select one or more terms from the drop-down list. To add your own filter term, enter the text string in the text box field.

• Bookmark: Saves the location of a log message, enabling you to find it quickly. To create a bookmark, either click the line number, or select some text and then click Bookmark.

• Preferences: Configures the text display used in the log message window.

• Refresh: Refreshes the log file you are currently viewing. Only log messages in the current tab are updated.

• Reload: Refreshes all log files. Log messages in every tab are updated.

• Settings: Displays the Settings window for the VM, enabling you to make configuration changes.

• Discard: For a running VM, discards the saved state for the VM and closes it down.

• Show/Start: For a running VM, Show displays the VM window. For a stopped VM, Start displays options for powering up the VM.

Note:

This key pair is not the same SSH key that you use to access compute instances on Oracle Cloud Infrastructure.

1. Click Add and specify a Name for the profile.

2. Select the new profile, and then click Properties. Specify the following property values for the profile:

   • Compartment OCID

   • Fingerprint of the public key

   • Location of the private key on the client device

   • Region OCID

   • Tenancy OCID

   • User OCID

   Some of these are settings for your Oracle Cloud Infrastructure account, which you can view from the Oracle Cloud Console.

3. (Optional) If you are using the cloud profile to connect to cloud virtual machines, select the Show VMs check box.

   This creates a new subgroup of the OCI group in VirtualBox Manager. See About the OCI VM Group.

4. Click Apply to save your changes.

   The cloud profile settings are saved to the oci_config file in your Oracle VirtualBox global settings directory.

You can also use VBoxManage cloudprofile to create a cloud profile. See Using VBoxManage Commands With Oracle Cloud Infrastructure.

Follow these steps to import an existing Oracle Cloud Infrastructure configuration file into the Cloud Profile Manager:

1. Ensure that a config file is present in your Oracle Cloud Infrastructure configuration directory. For example, this is $HOME/.oci/config on a Linux host.

2. Click the Import icon to open a dialog that prompts you to import cloud profiles from external files.

   Note:

   This action overwrites any cloud profiles that are in your Oracle VirtualBox global settings directory.

3. Click Import.

   Your cloud profile settings are saved to the oci_config file in your Oracle VirtualBox global settings directory.

4. Click Properties to show the cloud profile settings.

   Double-click the appropriate field to change the value.

5. Click Apply to save your changes.

Note:

Cloud VMs do not install, export, or import instances to the Oracle VirtualBox host. All operations are done remotely on the cloud service.

All cloud VMs are shown in the Machines list in VirtualBox Manager, in a special VM group called OCI.

Cloud VMs are further grouped according to the cloud profile used to connect to them. The cloud profile identifies the user and compartment for the cloud VM and includes details of the key pair used to connect to cloud instances. See Creating a Cloud Profile.

All cloud profiles registered with Oracle VirtualBox are listed automatically in the OCI group.

To enable or disable listing of cloud VMs in VirtualBox Manager for a specific cloud profile, follow these steps.

1. Display the Cloud Profile Manager.
2. Select or clear the List VMs check box for each cloud profile.

When you create a new cloud VM, a new Oracle Cloud Infrastructure instance is created and associated with the cloud VM.

Perform the following steps to create a new cloud VM:

1. Click a cloud profile in the OCI group.

   The cloud VMs for the selected cloud profile are displayed.

2. Select Group, New Machine.

3. Configure the following settings for the new cloud VM:

   • Location: The cloud service provider that will host the new instance. Select Oracle Cloud Infrastructure.

   • Profile: The cloud profile used to connect to the new instance. Select from the available cloud profiles.

   • Source: The image that the new instance is based on. Choose from the available images and boot volumes.

4. Change the Cloud Virtual Machine Settings as required. You will likely need to change the display name, shape, and networking configuration.

   To add an SSH key to the instance, click the SSH Authorised Keys field and paste the public key into the displayed dialog.

5. Click Finish to create a new Oracle Cloud Infrastructure instance using the selected image or boot volume. The new instance is started automatically.

   The new cloud VM is shown in the OCI group in VirtualBox Manager.

When you add a cloud VM, an existing Oracle Cloud Infrastructure instance is associated with the cloud VM. You can only add one cloud VM for each instance.

Perform the following steps to add a cloud VM:

1. Click a cloud profile in the OCI group.

   The cloud VMs for the selected cloud profile are displayed.

2. Select Group, Add Machine.

3. Configure the following settings:

   • Source: The cloud service provider that hosts the instance used for the cloud VM. Select Oracle Cloud Infrastructure.

   • Profile: The cloud profile used to connect to the running instance. Select from the available cloud profiles.

   • Instances: The instance to use for the cloud VM. Choose from the available instances on your cloud service.

4. Click Finish to add a cloud VM based on the selected instance.

   A cloud VM with the same name as the instance is added to the OCI group in VirtualBox Manager.

5. (Optional) To change the display name for the instance, click Settings and edit the Display Name field.

   The cloud VM name in VirtualBox Manager is updated automatically.

When you clone a cloud VM, a copy of the Oracle Cloud Infrastructure instance for the cloud VM is created and associated with the new cloud VM.

Perform the following steps to clone a cloud VM:

1. Click a cloud profile in the OCI group.

   The cloud VMs for the selected cloud profile are displayed.

2. Right-click the cloud VM you want to clone and select Clone.

   The Clone Name dialog is displayed.

   Enter a name for the clone.

   The name you enter is also used as the display name for the related Oracle Cloud Infrastructure instance. The default name for the clone consists of the _clone suffix appended to the original name. For example, ol9-dev_clone.

3. Click OK to create the clone and the related Oracle Cloud Infrastructure instance. The new instance is started automatically.

   The new cloud VM is shown in the OCI group in Machines in VirtualBox Manager.

Select the cloud VM in VirtualBox Manager and click Settings.

• For a new cloud VM, you can change many settings for the Oracle Cloud Infrastructure instance, such as the display name, shape, and disk size.

• When you add a cloud VM based on an existing Oracle Cloud Infrastructure instance you can only change the display name.

You can use VirtualBox Manager to control a cloud VM as follows:

• Start. Use the Start button in the Machines toolbar.

• Stop. Click the cloud VM name and select Machine, Stop. Menu options to shut down and power off the cloud VM are available.

• Reset. Click the cloud VM name and select Machine, Reset. The cloud VM is stopped, then restarted automatically.

• Terminate. Use the Terminate button in the VirtualBox Manager toolbar.

  CAUTION:

  This action deletes the instance from Oracle Cloud Infrastructure.

When you control a cloud VM in VirtualBox Manager the machine list is updated automatically with the current instance state, such as Stopped or Running.

When you control an instance using the Oracle Cloud Infrastructure console, VirtualBox Manager updates the status for the corresponding cloud VM automatically.

You can monitor the performance of cloud VM instances in the following ways:

• Use the virtual machine monitoring tools in VirtualBox Manager.

  • To show detailed performance data for a cloud VM:

    Click the cloud VM name in the Machines list and click Resource Use.

    Several time series charts are displayed, showing resource usage and performance data. To save the data to file, click Export.

  • To show a performance summary for all cloud VMs:

    Click Resources to see a summary of performance metrics for all running cloud VMs and for the host system.

  See also Monitoring of Virtual Machines.

• Use the VBoxManage cloud instance command, as follows:

  • VBoxManage cloud instance metriclist shows the available metrics for an instance.

  • VBoxManage cloud instance metricdata shows metrics data for an instance.

  See also VBoxManage cloud.

You can use VirtualBox Manager to remove a cloud VM as follows:

Right-click the cloud VM name and select Remove.

• Click Remove Only to remove the cloud VM from the Machines list in VirtualBox Manager.

• Click Delete Everything to remove the cloud VM from VirtualBox Manager and also to delete the Oracle Cloud Infrastructure instance and any associated boot volumes.

To create a instance console connection, the cloud VM must be in Running state.

1. Right-click the cloud VM name and select Console, Create Connection.

2. The Public Key dialog is displayed. Paste the public key used for the instance connection into the dialog and click OK.

   By default, either the first entry in your SSH keys folder or the public key used for your previous instance console connection is used.

3. Click Connect to connect to the instance. An instance console is displayed automatically on the host.

4. (Optional) Click Show Log to display log messages for the instance console connection.

See the Oracle Cloud Infrastructure documentation for details about how you can use an instance console connection to troubleshoot instance problems.

Note:

Before you export a VM to Oracle Cloud Infrastructure, you must prepare the VM as described in Preparing a VM for Export to Oracle Cloud Infrastructure.

Oracle Cloud Infrastructure provides the option to import a custom Linux image. Before an Oracle VirtualBox image can be exported to Oracle Cloud Infrastructure, the custom image needs to be prepared to ensure that instances launched from the custom image can boot correctly and that network connections will work. This section provides advice on how to prepare a Linux image for export from Oracle VirtualBox.

The following list shows some tasks to consider when preparing an Oracle Linux VM for export:

• Use DHCP for network addresses. Configure the VM to use a DHCP server to allocate network addresses, rather than using a static IP address. The Oracle Cloud Infrastructure instance will then be allocated an IP address automatically.

• Do not specify a MAC address. The network interface configuration for the VM must not specify the MAC address.

  Remove the HWADDR setting from the /etc/sysconfig/ifcfg-devicename network script.

• Disable persistent network device naming rules. This means that the Oracle Cloud Infrastructure instance will use the same network device names as the VM.

  1. Change the GRUB kernel parameters.

     Add net.ifnames=0 and biosdevname=0 as kernel parameter values to the GRUB_CMDLINE_LINUX variable.

  2. Update the GRUB configuration.

     # grub2-mkconfig -o /boot/grub2/grub.cfg

  3. Disable any udev rules for network device naming.

     For example, if an automated udev rule exists for net-persistence:

     # cd /etc/udev/rules.d
     # rm -f 70-persistent-net.rules
     # ln -s /dev/null /etc/udev/rules.d/70-persistent-net.rules

• Enable the serial console. This enables you to troubleshoot the instance when it is running on Oracle Cloud Infrastructure.

  1. Edit the /etc/default/grub file, as follows:

     • Remove the resume setting from the kernel parameters. This setting slows down boot time significantly.

     • Replace GRUB_TERMINAL="gfxterm" with GRUB_TERMINAL="console serial". This configures use of the serial console instead of a graphical terminal.

     • Add GRUB_SERIAL_COMMAND="serial --unit=0 --speed=115200". This configures the serial connection.

     • Add console=tty0 console=ttyS0,115200 to the GRUB_CMDLINE_LINUX variable. This adds the serial console to the Linux kernel boot parameters.

  2. Regenerate the GRUB configuration.

     # grub2-mkconfig -o /boot/grub2/grub.cfg

  3. To verify the changes, reboot the machine and run the dmesg command to look for the updated kernel parameters.

     # dmesg |grep console=ttyS0

• Enable paravirtualized device support. You do this by adding the virtio drivers to the initrd for the VM.

  1. This procedure works only on machines with a Linux kernel of version 3.4 or later. Check that the VM is running a supported kernel:

     # uname -a

  2. Use the dracut tool to rebuild initrd. Add the qemu module, as follows:

     # dracut –-logfile /var/log/Dracut.log --force --add qemu

  3. Verify that the virtio drivers are now present in initrd.

     # lsinitrd |grep virtio

For more information about importing a custom Linux image into Oracle Cloud Infrastructure, see also:

Importing Custom Linux Images.

The following describes the sequence of events when you import an instance from Oracle Cloud Infrastructure.

• A custom image is created from the boot volume of the instance.

• The custom image is exported to an Oracle Cloud Infrastructure object and is stored using Object Storage in the bucket specified by the user.

• The Oracle Cloud Infrastructure object is downloaded to the local host. The object is a TAR archive which contains a boot volume of the instance in QCOW2 format and a JSON file containing metadata related to the instance.

• The boot volume of the instance is extracted from the archive and a new VMDK image is created by converting the boot volume into the VMDK format. The VMDK image is registered with Oracle VirtualBox.

• A new VM is created using the VMDK image for the cloud instance.

  By default, the new VM is not started after import from Oracle Cloud Infrastructure.

• The downloaded TAR archive is deleted after a successful import.

Mount the Guest Additions ISO

1. Start the virtual machine. The OS must be installed.

2. From the Devices menu, choose Insert Guest Additions CD Image, which mounts the Guest Additions ISO file inside your VM.

3. If this option is not available, or if you prefer to mount the ISO manually:

   1. From the Devices menu, choose Optical Drives, and then Choose/Create a Disk Image. This displays The Virtual Media Manager.

   2. In the Virtual Media Manager, click Add and browse your host file system for the VBoxGuestAdditions.iso file.

      • On a Windows host, this file is in the Oracle VirtualBox installation directory, usually in C:\Program files\Oracle\VirtualBox.

      • On a Linux host, this file is in the additions folder where you installed Oracle VirtualBox, usually /opt/VirtualBox/.

      • On Oracle Solaris hosts, this file is in the additions folder where you installed Oracle VirtualBox, usually /opt/VirtualBox.

   3. In the Virtual Media Manager, select the ISO file and click Add. This mounts the ISO file and presents it to your guest OS as a CD-ROM.

Run the Guest Additions Installer

1. Mount the ISO as described in the previous task.

2. Unless you have the Autostart feature disabled, or it is not supported, the OS will now autostart the Oracle VirtualBox Guest Additions installer from the Guest Additions ISO.

   If the Autostart feature has been turned off, choose VBox<OS>Additions.exe from the CD/DVD drive inside the guest to start the installer, where <OS> is Windows, Linux, OS2 or Solaris.

3. Follow the instructions in the installer.

4. Reboot the guest OS.

The Oracle VirtualBox Windows Guest Additions are designed to be installed in a virtual machine running a Windows operating system. The Windows Guest Additions will run on VMs running these versions of Windows. See also Host and Guest Combinations.

Installing the Windows Guest Additions

VBoxWindowsAdditions.exe /S

VBoxWindowsAdditions.exe /?

Updating the Windows Guest Additions

Installing Code Signing Certificates

Automated Windows System Preparation

The Oracle VirtualBox Guest Additions for Linux are a set of device drivers and system applications that may be installed in the guest operating system. The Linux Guest Additions will run on VMs running these versions of Linux. See also Host and Guest Combinations.

The guest additions may also work on other distributions.

Installing the Linux Guest Additions

Manual Setup of Selected Guest Services on Linux

$ sh ./VBoxLinuxAdditions.run no_setup

Linux Guest Screen Resizing

VBoxManage guestproperty unset "VM name" /VirtualBox/GuestAdd/DRMIpcRestricted

Updating the Linux Guest Additions

Uninstalling the Linux Guest Additions

sh ./VBoxLinuxAdditions.run uninstall

/opt/VBoxGuestAdditions-version/uninstall.sh

The Oracle VirtualBox Guest Additions for Oracle Solaris take the form of a set of device drivers and system applications which may be installed in the guest operating system.

The Solaris Guest Additions will run on VMs running these versions of Solaris. See also Host and Guest Combinations.

• Oracle Solaris 11, including Oracle Solaris 11 Express

• Oracle Solaris 10 4/08 and later

The Guest Additions may work with other distributions that are based on comparable software releases.

Installing the Oracle Solaris Guest Additions

svcadm restart volfs

pkgadd -G -d ./VBoxSolarisAdditions.pkg

Uninstalling the Oracle Solaris Guest Additions

pkgrm SUNWvboxguest

Updating the Oracle Solaris Guest Additions

The Guest Additions should be updated by first uninstalling the existing Guest Additions and then installing the new ones. Attempting to install new Guest Additions without removing the existing ones is not possible.

Oracle VirtualBox also includes a set of drivers that improve running OS/2 in a virtual machine. Due to restrictions of OS/2 itself, this variant of the Guest Additions has a limited feature set. Specifically, seamless windows and automatic guest resizing are not implemented in Guest Additions for OS/2 because of inherent limitations of the OS/2 graphics system.

The OS/2 Guest Additions are provided on the same ISO CD-ROM as those for the other platforms. Mount the ISO in OS/2 as described in Installing Guest Additions. The OS/2 Guest Additions are located in the directory \OS2.

We do not provide an automatic installer. See the readme.txt file in the CD-ROM directory, which describes how to install the OS/2 Guest Additions manually.

Note:

At the moment only copying of data is supported. Moving or linking is not yet implemented.

Note:

Drag and drop support depends on the frontend being used. At the moment, only the VirtualBox Manager frontend provides this functionality.

As Oracle VirtualBox can run on a variety of host operating systems and also supports a wide range of guests, certain data formats must be translated after transfer. This is so that the destination operating system, which receives the data, is able to handle them in an appropriate manner.

The following formats are handled by the Oracle VirtualBox drag and drop service:

• Plain text: From applications such as text editors, internet browsers and terminal windows.

• Files: From file managers such as Windows Explorer, Nautilus, and Finder.

• Directories: For directories, the same formats apply as for files.

The properties /VirtualBox/HostInfo/VBoxVer, /VirtualBox/HostInfo/VBoxVerExt or /VirtualBox/HostInfo/VBoxRev can be waited on to detect that the VM state was restored from saved state or snapshot:

$ VBoxControl guestproperty wait /VirtualBox/HostInfo/VBoxVer

Similarly the /VirtualBox/HostInfo/ResumeCounter can be used to detect that a VM was resumed from the paused state or saved state.

Note:

To use the Guest Control File Manager, the guest must be running. For powered-off guests, it is disabled automatically.

To use the Guest Control File Manager to transfer files, follow these steps.

1. Ensure you have the username and password for an account on the guest system, with appropriate permissions on the files you need to access.

2. Open the Guest Control File Manager. Do either of the following:

   • In the guest VM, select Machine, File Manager.

   • In VirtualBox Manager, Machines list, click the machine name, and then select File Manager.

   The Host File System pane shows the files on the host system.

3. In the Guest File System pane, enter the User Name and Password for the user you want to log in as.

   Click Open Session.

   The VM file system appears in the Guest File System pane.

4. To transfer from the VM to the host, select the file(s) and click Copy From Guest to Host.

   To transfer from the host to the VM, select the file(s) and click Copy From Host to Guest.

5. Check the progress of the transfer in the Operations pane.

6. Click Close to end the guest session and the Guest Control File Manager.

The Guest Additions can change the amount of host memory that a VM uses, while the machine is running. Because of how this is implemented, this feature is called memory ballooning.

Normally, to change the amount of memory allocated to a virtual machine, you have to shut down the virtual machine entirely and modify its settings. With memory ballooning, memory that was allocated for a virtual machine can be given to another virtual machine without having to shut the machine down.

When memory ballooning is requested, the Oracle VirtualBox Guest Additions, which run inside the guest, allocate physical memory from the guest operating system on the kernel level and lock this memory down in the guest. This ensures that the guest will not use that memory any longer. No guest applications can allocate it, and the guest kernel will not use it either. Oracle VirtualBox can then reuse this memory and give it to another virtual machine.

The memory made available through the ballooning mechanism is only available for reuse by Oracle VirtualBox. It is not returned as free memory to the host. Requesting balloon memory from a running guest will therefore not increase the amount of free, unallocated memory on the host. Effectively, memory ballooning is therefore a memory overcommitment mechanism for multiple virtual machines while they are running. This can be useful to temporarily start another machine, or in more complicated environments, for sophisticated memory management of many virtual machines that may be running in parallel depending on how memory is used by the guests.

At this time, memory ballooning is only supported through VBoxManage. Use the following command to increase or decrease the size of the memory balloon within a running virtual machine that has Guest Additions installed:

VBoxManage controlvm "VM name" guestmemoryballoon n

where VM name is the name or UUID of the virtual machine in question and n is the amount of memory to allocate from the guest in megabytes. See VBoxManage controlvm.

You can also set a default balloon that will automatically be requested from the VM every time after it has started up with the following command:

VBoxManage modifyvm "VM name" --guest-memory-balloon n

By default, no balloon memory is allocated. This is a VM setting, like other modifyvm settings, and therefore can only be set while the machine is shut down. See VBoxManage modifyvm.

Whereas memory ballooning simply reduces the amount of RAM that is available to a VM, Page Fusion works differently. It avoids memory duplication between several similar running VMs.

In a server environment running several similar VMs on the same host, lots of memory pages are identical. For example, if the VMs are using identical operating systems. Oracle VirtualBox's Page Fusion technology can efficiently identify these identical memory pages and share them between multiple VMs.

The more similar the VMs on a given host are, the more efficiently Page Fusion can reduce the amount of host memory that is in use. It therefore works best if all VMs on a host run identical operating systems. Instead of having a complete copy of each operating system in each VM, Page Fusion identifies the identical memory pages in use by these operating systems and eliminates the duplicates, sharing host memory between several machines. This is called deduplication. If a VM tries to modify a page that has been shared with other VMs, a new page is allocated again for that VM with a copy of the shared page. This is called copy on write. All this is fully transparent to the virtual machine.

You may be familiar with this kind of memory overcommitment from other hypervisor products, which call this feature page sharing or same page merging. However, Page Fusion differs significantly from those other solutions, whose approaches have several drawbacks:

• Traditional hypervisors scan all guest memory and compute checksums, also called hashes, for every single memory page. Then, they look for pages with identical hashes and compare the entire content of those pages. If two pages produce the same hash, it is very likely that the pages are identical in content. This process can take rather long, especially if the system is not idling. As a result, the additional memory only becomes available after a significant amount of time, such as hours or sometimes days. Even worse, this kind of page sharing algorithm generally consumes significant CPU resources and increases the virtualization overhead by 10 to 20%.

  Page Fusion in Oracle VirtualBox uses logic in the Oracle VirtualBox Guest Additions to quickly identify memory cells that are most likely identical across VMs. It can therefore achieve most of the possible savings of page sharing almost immediately and with almost no overhead.

• Page Fusion is also much less likely to be confused by identical memory that it will eliminate, just to learn seconds later that the memory will now change and having to perform a highly expensive and often service-disrupting reallocation.

At this time, Page Fusion can only be controlled with VBoxManage, and only while a VM is shut down. To enable Page Fusion for a VM, use the following command:

VBoxManage modifyvm "VM name" --page-fusion on

You can observe Page Fusion operation using some metrics. RAM/VMM/Shared shows the total amount of fused pages, whereas the per-VM metric Guest/RAM/Usage/Shared will return the amount of fused memory for a given VM. See VBoxManage metrics for information on how to query metrics.

The Guest Additions provide services for controlling the guest system's monitor topology. Monitor topology means the resolution of each virtual monitor and its state (disabled/enabled). The resolution of a virtual monitor can be modified on the VM by using the View menu, or from the host side by resizing the window that hosts the virtual monitor, or the VBoxManage controlvm vmname setscreenlayout command. See Specify the Screen Layout for a Display on the Guest VM. Screens enabled must be contiguous or the command will have no effect.

On guest operating systems with X11/XWayland desktops this is put into effect by any of the following services:

VBoxClient --vmsvga

VBoxClient --vmsvga-session

VBoxDRMClient

On X11/XWayland desktops the resizing service is started during desktop session initialization, that is desktop login. On X11 desktops VBoxClient --vmsvga handles screen topology through the RandR extension. On XWayland clients VBoxDRMClient is used. The decision is made automatically at each desktop session start.

On 32-bit guest operating systems VBoxDRMClient is always used, in order to work around bugs.