RHEL Slim Down
Learn how to slim down RHEL and its images for creating reduced images for disks
Pablo Iranzo Gómez blog
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RHEL bootable containers (BOOTC)
Learn how to use a container for being the baseline for your computer, making it easier to operate the operating system installation and maintenance.
Enable GPU acceleration with the Kernel Module Management Operator
Learn how to enable GPU acceleration with the Kernel Module Management (KMM) Operator so you can can run AI workloads on top of Intel Data Center GPU Flex 140.
Install gems on local user folder instead of system wide
In order to test locally a Gemfile, define local path for the gems to avoid attempting to write to system-wide folders: bundle config set --local path '/home/username/.gem' bundle install
Advice for Telegram usage in education
Telegram is being used frequently at schools for allowing an easy communication flow using the ‘channels’, where teachers can send information to families without sharing their personal contact details so that they can’t be contacted outside of the official tools. This comfort, came, probably because of not knowing the problems/dangers that were not taken into consideration. For…
Red Hat Co.Lab for the day of Science for Development "Conversation Machine"
Red Hat has a program named Co.Lab which provides kits under request that employees can use to guide a STEM session on schools to perform different range of activities. We performed 2 sessions this year, one for the “We Are Red Hat Week” ( WARHW ), which happens every year around Halloween, when the first official release was launched back in 31st October 1994 ( ‘Halloween…
OpenShift Layered Images for patching
With recent releases of OpenShift like 4.13 you can use CoreOS Layering to apply custom images to the nodes. The feature allows to build, via a Dockerfile a custom image that can later be applied to our nodes. Let’s review the steps: First we need to find the base image being used in our environment with oc adm release info quay.io/openshift-release-dev/ocp-release:4.13.5-aarch64…
mydlink Website from Linux
Hi had the chance to buy a Dlink camera, waterproof, with magnetic base and rated for exteriors for a really great price a while ago D-Link DCS 8600LH 🛒#ad and later a camera with pan and tilt from Dlink too D-Link DCS-6500LH 🛒#ad The camera, of course has an application for configuration, viewing the image, etc named ‘mydlink’ which has a web counterpart at https://mydlink.com/ ,…
No matching key found
As you might have experienced… using a recent system to connect to a legacy one could be complicated as some insecure protocols have been disabled, with a message like: Unable to negotiate with 192.168.2.82 port 22: no matching host key type found. Their offer: ssh-rsa,ssh-dss Create an entry like this in your .ssh/config file, so that insecure methods can be used to connect to a specific…
Upgrade Debian from buster to bullseye
I had two Raspberry Pi systems running Raspbian and they were failing to find updates for newer packages. As Debian stable was upgraded too, moving from buster to bullseye the packages failed to get the newer ones. Warning Beware as this procedure might upgrade the system but might no render a bootable Raspberry Pi A way to fix it is, to first, change references, if any, to the old codename…
KMM 1.1 Scale testing
Attention First published at https://cloud.redhat.com/blog/scale-testing-kernel-module-management Introduction Kernel Module Management (KMM) Operator manages, builds, signs and deploys out-of-tree kernel modules and device plugins on OpenShift Container Platform clusters. KMM adds, for the HUB/Spoke scenario, a new ManagedClusterModule which describes an out-of-tree kernel module and its…
Showing calendar events in Telegram
If you’ve a Telegram group, it might be interesting the ability of https://t.me/redken_bot for adding a calendar ical that automates publishing each day the events in the agenda for the day. If you did read Python and iCalendar ICS processing , part of the basis in that article are part of the bot and are easily used: For configuring, only a few simple steps are required: Have a calendar…
Automating SSH keys loading for Ansible usage
For using Ansible it’s required to have a working set of ssh-keys already deployed. If you get a set of systems that have not been provisioned by you and are missing the SSH keys, having it fixed might take a while if doing it manually. Good news is that you can use a script in expect to cover this part: #!/usr/bin/expect -f # set Variables set password [lrange $argv 0 0] set ipaddr [lrange…
Using ChatGPT for writing Risu Plugins
Lately, there’s a lot of interest on ChatGPT , and yes, it’s really impressive the way it processes the context to provide answers to the questions. To give it a try, and put into play the requirements for writing a Risu plugin, I wrote some of the requirements in a paragraph: I want to create a bash script for checking system status. The script should use return codes to indicate…
Enable rootless podman on Fedora
With podman we can setup containers for being used for non root users by performing some simple steps: Install required packages dnf -y install slirp4netns fuse-overlayfs crun podman shadow-utils Force the number of user namespaces (might be required on some environments): echo 'user.max_user_namespaces=28633' > /etc/sysctl.d/userns.conf sysctl -p /etc/sysctl.d/userns.conf Delegate Allows to…
Kernel Module Management testing
Following on the Using Kcli to prepare for OCM testing , we’re going to prepare KMM testing in Hub-Spoke approach. First we need to prepare our .docker/config.json with the contents of our OpenShift pull secret used with Kcli . mkdir -p ~/.docker/ cp openshift_pull.json ~/.docker/config.json Warning advisories Note Semi-scripted version available at automate.sh Warning We’re using…
Management Integration whereabouts
Management Integration whereabouts What we’ve done so far? ZTP Factory Workflow Kernel Module Management NVIDIA Bluefield support OpenShift Virtualization with vGPU Other supporting tasks ZTP Factory Workflow ZTP Stands for Zero Touch Provisioning: Automated OpenShift deployment that setup registry mirror, nodes,etc out of a configuration yaml. The architecture was described as Openshift…
Enable Libvirt rw socket on RHEL9
RHEL9 by default uses read-only socket which is not usable by some tools like Kcli … to enable it use: systemctl enable --now libvirtd.socket libvirtd-ro.socket systemctl stop libvirtd.service systemctl enable --now virtproxyd.socket virtproxyd-ro.socket systemctl stop virtproxyd.service
Using Kcli to prepare for Open Cluster Management testing
Kcli allows to quickly interact with different virtualization platforms to build machines with some specific configurations, and via the use of plans it allows to automate most of the setup required to have an environment ready. In our case, let’s setup an environment to practice with Open Cluster Management but instead of using kind clusters, let’s use VM’s. Note We’ll…
[python] Generate ranges from items
Some years ago, I added a script for updating headers for (C) in the python files I was developing for Risu . In this way, the header got the list of authors and years working on the files updated automatically. With the pass of the years, the list started to became a bit too long, so I worked on creating code for getting ranges instead. This is the code I used: def getranges (data): ''' From list…
Automate code build and deployment with ansible
Let’s say that we want to keep our system updated with some code which is not distributed as a regular package, but as a code in a repository (which unfortunately, it’s a pretty common situation). As a part of the ansible playbooks used for the hosts, I can add a snippet like this: gitrepos : - { url : 'https://github.com/myrepo/repo.git' , tag : 'tagtocheckout' , folder :…
OpenShift's oc debug and parallel execution
A colleague reported some issues in the OpenShift troubleshooting and diagnosis scripts at OpenShift-checks . Some time ago I did contribute some changes to use functions and allow using the RISU wrapper to the scripts, helping consuming the results via RISU’s HTML interface. As my colleague reported, for some plugins, the output of the command was not shown in the HTML Interface. After some…
[Book] Red Hat Enterprise Linux 9 Administration
RHEL9 System Administration book now available!
Ansible - dynamically include Jinja templates and tasks
For my ansible playbooks, I wanted to be able to add several new templates to be copied to target system, and additionally be able to perform some commands for them without having to specify each individual file/template to copy. My approach: Define for the hosts I want to find templates/playbooks define a var named extras for the relevant hosts: extras : - ntp - certificates The names defined (in…
Include Ansible playbooks sorted
Use sorted list for included files vs random provided by with_fileglob . - name : Include tasks include_tasks : '{{item}}' loop : '{{ query('fileglob', 'tasks/*.yaml') | sort }}'
Setup a Quay mirror for offline installations with mirror-registry
Learn on how to use mirror-registry to create a local copy that can be used to install OpenShift without external Internet connectivity.
Check Agent status per state
Check agent status per state watch -d 'oc get agent -A -o jsonpath='{range .items[*]}{@.status.debugInfo.state}{\'\n\'}{end}' |sort | uniq --count'
RHCE and RHCSA tips and tricks
I did the RHCE exam some time ago, and still there are some tricks and advices I tell the people to bear in mind some of the things I used and that were also provided in the Red Hat Enterprise 8 Administration book: Don’t remember every step, it’s not effective, for example as I don’t recall syntax for BIND, I do remember package that has some files with examples and I use that…
Lego 60335 Train station with bus
I loved the Bus and I was behind it for my city setup, so I went for it and got the Lego 60335 Train station with bus . It contains three instruction manuals for the components: Cart for repairs that can run over the tracks or the road Bus Train station itself The train station. It features a cafeteria with a croissant, coffee machine and another desk for the tickets. Has ticket machine and a…
Lego Volkswagen T2
I’ve been building the Lego Volkswagen T2 🛒#ad and took some pics about the final result and the comparison with the T1 . Feelings: The rear door (above the motor) dismantles itself just by looking at it, the mechanism is interesting as it uses some sticks that get inserted inside the support, but the frame holding it, specially in the upper side is really weak… The sliding door on…
Unsupported upgrade for RHEL-based distributions without reinstallation
Most systems, based on RHEL, were not able to upgrade without reinstallation, or best said, not supported. The new version, that was released at around 18 months later contained so many changes that it was hard to test the upgrades themselves until leapp was introduced. Check the lifecycle here: https://access.redhat.com/support/policy/updates/errata However, the biggest problem could be the…
Lego The SkyWalker Saga Codes
Inside the game The Sky Walker Saga PS4 , PS5 , Xbox , Nintendo Switch , you can introduce some codes to unlock additional characters to use, so far this is the list I’ve found: Code Character/vehicle 3FCPPVX Tarkin ARVALA7 Razor Crest BAC1CKP Mister Bones C3PHOHO C-3P0 (Party special) GR2VBXF Ratts Tyerell KH7P320 Aayla Secura KORDOKU Poe Dameron (Party special) LIFEDAY GNK Droid (Party…
Logitech R400 remote presentation controller on Linux
Since long ago I had it in my mind getting one remote presenter, but most presenters just had two buttons, and the ones that looked to be valid for my use case, required four and seems that only Rii had similar devices, but I didn’t went for it as it was not a huge need, so I ended up with a mini keyboard I had for Raspberry Pi and some debugging in case I had that need.
Ansible setup for VPN using WireGuard
Learn on how to setup a VPN using WireGuard using Ansible
Zero Touch Provisioning OpenShift for Edge computing
This article describes how to use python to bind against an LDAP server and perform queries
In action...@redken_bot with examples
See how to use @redken_bot in Telegram or discord with some examples!
LDAP query from Python
This article describes how to use python to bind against an LDAP server and perform queries
How to stake on NYM Validator 🐳🐳🐳
This article describes how to stake your token against a NYM cosmos validator
The experience of writing a book
I wanted to write about my experience (before I forget about it), and as some colleagues asked about it… here we go… As published in the blog entry RHEL8 Administration book , some colleagues and I wrote a book on RHEL8 administration, which can be bought here . Many years ago I started one about Linux, but every time a new paragraph was added, a lot of new ‘TO-DO’ items…
[Book] Red Hat Enterprise Linux 8 Administration
RHEL8 System Administration book now available!
Lego exclusive materials for Technic Owners
Lego promotional material for Technic Owners using your own's car license plate
imapfilter for Gmail
Learn on how to use imapfilter against Gmail for classifying the messages
UEFI boot order change
Hi, In case you’ve a dual boot machine, sometimes it might happen that grub menu is no longer appearing. For systems using regular BIOS, a grub-install against the device it was installed might be required, but when using UEFI, it’s really easy to use a rescue media and execute efibootmgr to alter the boot order. When executing efibootmgr , it might output some information like this:…
Redken machine learning for spam detection
For some of the telegram groups I’m in, I’ve been detecting users that after some period of time, just publish spam messages of any topic. There are many bots for controlling when a user joins, by showing a CAPTCHA that user must resolve (either clicking a button, answering a mathematical operation, inputting a CAPTCHA image text, etc). Some time ago, a colleague was using Machine…
Geo replication with syncthing
Some years ago I started using geo replication to keep a copy of all the pictures, docs, etc After being using BitTorrent sync and later resilio sync (even if I didn’t fully liked the idea of it being not open source), I gave up. My NAS with 16 GB of ram, even if a bit older (HP N54L), seemed not to have enough memory to run it, and was constantly swapping.
How to check if a system is virtual
I was improving a playbook in Ansible and wanted to find a way to find if a system was virtual or not to decide about some tunning like setting tuned-adm profile virtual-guest or disable the power off when the lid is closed. After some research and try-except situations I got to this one that seemed to work (I had to tune it as one desktop machine was missing the /sys entry I was using before):
How to run a NYM Validator
As said in the article about mixnodes , NYM is a technology aiming for providing privacy for the communications. Apart of the mixnodes, other key piece in the infrastructure are the validators. As said, the project uses Open Source technology to run, and they have a nice docs with details on how to run a node at https://nymtech.net/docs/ , and the one relevant for mixnodes at…
How to run a NYM mixnode
Some time ago I’ve started running a NYM mixnode. NYM is a project that targets improving privacy by decomposing network packages from different hosts, so that origin and target cannot be traced. You can check more about the NYM project at their site at https://nymtech.net/ . The project uses Open Source technology to run, and they have a nice docs with details on how to run a node at…
Lego Technic 42115 Lamborghini Sian FKP47
Xmas came with a good gift that I was able to finish mounting today, the Lego Lamborghini Sian FKP47 🛒#ad . The build experience was good, except for some issues related with not building in the best conditions of light, but more or less fixable… I forgot to add a gear that required me to bend a bit the model to put it back Realized that the gear shift wasn’t working because I…
Be lazy, automate: GitHub actions for static blogging
Be lazy, automate: GitHub Actions for static blogging /me: Pablo Iranzo Gómez ( https://iranzo.io ) What is a blog? A place to share knowledge, interests, tips, etc. Usually features: images comments from visitors, related articles, etc. What are the costs for a blog? Web costs money: Hosting Domain Maintenance etc. What is static blogging? Generate a static webpage Think of it as rendering…