README.md

Docker usage exercices

images

docker run: starts container with given image.
docker ps: displays list of available containers.
docker stop: stops the container.
docker rm: removes stopped container.
docker images: displays list of images.
docker rmi: removes unused images.
docker build: builds image from dockerfile.
docker-compose up: launches application built with multiple containers.
docker exec: launches command in running container.
docker logs: displays logs from running container.
docker inspect: shows info about container / image.

Exercises:

• Pull docker image alpine and build Dockerfile which would copy local item .txt to container. Set /bin/sh the default action for container.

  Solution

  FROM alpine
  WORKDIR /app
  COPY file.txt .
  CMD ["/bin/sh"]

  Then it would use bash command in Dockerfile to replace all characters A with B and would save it to file2.txt.

  #Command to use:
  sed "s/A/B/g" file.txt | tee file2.txt

  Run newly created container with docker run -it command. Use command docker ps to find latest container ID of container using your image.

  Solution

  docker run -it ImageID

  In seperated terminal try to access logs from this container. Use docker logs -f ContainerID command.

  Execute bash command to see file2.txt content on running container to see output. Try to make it in the same terminal window where you used docker run -it and try to execute docker exec containerId cat file2.txt. Try to explain the observation.

  Solution

  `docker logs` shows you only output from CMD/Entrypoint of container and skipping any other output. It is because we are getting information only from one single shell.

TODO - DOCKER MULTI STAGE