DevOps Classroom notes 27/May/2026

Docker lifecycle

Common docker commands

• A container is running and you want to see the logs

docker logs <contaner-id or name>
docker logs <contaner-id or name> -f

• Docker logs shows only stdout and stderr
• I want to delete all containers in my system

docker rm -f $(docker ps -a -q)

• I want to delete all images in my system

docker rmi $(docker image ls -q)

• You want to clean the images, volumes which are not being used

docker system prune -a

• You have a container running and for some reason you want to copy a file into it

docker cp <file> <container-name-or-id>:<path>
docker cp 1.txt test1:/

• You can copy the files from container into local system

docker cp <container-name-or-id>:<path> <file>

• Inspect commands

docker image inspect <id>
docker container inspect <id>

How are images built and organized

• Docker image is collection of read-only image layers and these layers are created during building images.
• Try to create minimal layers

RUN apt update \
    && apt install tree &&\
    apt install mysql-client