Docker intro

https://medium.com/@kelvin_sp/docker-introduction-what-you-need-to-know-to-start-creating-containers-8ffaf064930a

CMD, ENTRYPOINT

https://medium.freecodecamp.org/docker-entrypoint-cmd-dockerfile-best-practices-abc591c30e21

./entrypoint.sh

https://www.youtube.com/watch?v=4EqysCR3mjo

Build and run multi-container apps. One form is Docker Compose file, also docker-compose command.

entrypoint: /entrypoint.sh
CMD (Dockerfiles) / command (Docker Compose files)

https://docs.docker.com/compose/overview/

Docker compose files, "network". Can only run docker compose on single machine. Swarm is the orchestration solution provided by docker. (cluster)

docker-compose build
docker-compose up -d
docker network ls

Refer to the container by the name of the service

Secrets are used in Docker Swarm

dockerfile option within docker-compose build section

docker-compose ps
docker-compose logs -f
docker-compose stop # does not remove containers
docker-compose start
docker-compose restart

Execute redis query on redis-cli, from within docker redis

docker-compose exec redis redis-cli lrange students 0 -1
docker-compose exec app /bin/bash # start up a shell
docker-compose run... # starts up a new container, as opposed to exec uses a running container

Port mapping will not be intact in this case

Can change port mapping, e.g. from 5000:5000 to 80:5000, and do another docker-compose up and everything is updated. Can do a curl localhost and get the desired response on port 80

Scaling

Start more than one container for a service

docker-compose up --scale app=3

Volumes

docker volume ls

Networks

docker network ls
docker network prune

Docker compose push to push to a repository

Docker compose pull to download all the images necessary. (Docker playground)

.env file

How to use multiple compose files in a single project

e.g. docker-compose.override.yml

e.g. make it run on port 5000 and port 80