Docker

Containers are meant to run a specific task or process.

Commands

docker ps -a

docker images

docker build webapp-color -t webapp-color:tag

docker run -p 8282:8080 webapp-color (host port:container port)

docker run -e APP_COLOR=pink simpleapp

docker run -it python:3.6 sh

cat /etc/resolv.conf - system version

CMD ["executable", "param1"] or CMD executable param1

CMD allows to set a default command which can be overriden by docker run ubuntu [COMMAND] for example docker run ubuntu sleep 5

ENTRYPOINT specifies a program that will be run at startup.

When overriding CMD is replaced and ENTRYPOINT stays and appends args.

FROM Ubuntu

ENTRYPOINT ["sleep"]

CMD ["5"]

docker run ubuntu-sleeper -> sleep 5 docker run ubuntu-sleeper 10 -> sleep 10 docker run --entrypoint sleep2.0 ubuntu-sleeper 10 -> sleep2.0 10

ps aux - processes

docker run --user=1000 ubuntu sleep 3600 - run as user

or in Dockerfile USER 1000

System privileges can be added/removed with docker run --cap-add MAC_ADMIN ubuntu and `docker run --cap-drop KILL ubuntu.

Container can be run with all privileges with docker run --privileged ubuntu.