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Docker Cheatsheet

January 17, 2025 · 2 min read · Page View:
Cheatsheet
Docker

Docker cheatsheet

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This is a cheatsheet of docker.

Note: the docs will be updated from time to time.

Deamon #

  • docker info
  • systemctl start | stop | restart | status | enable docker This command to operate the docker daemon. For more details, you can refer to the systemd.
  • docker system df query the disk usage of the docker

images #

  1. docker push <username>/<image_name>
  2. docker images
  3. docker pull | inspect | rmi ubuntu:20.04
    • normally, the image name is composed by registry/username/repository:tag, if there is no username, the default is library, which is the official repository. if there is no registry, the default is docker.io, which is the official registry.
  4. docker create -it ubuntu:20.04 create a container by the image
  5. docker tag image_name:tag new_image_name:new_tag
  6. docker export/import and docker save/load
  • export/import will discard history and metadata information, only saving the snapshot state of the container at the time
    • docker export -o xxx.tar CONTAINER
    • docker import xxx.tar image_name:tag
  • save/load will save the complete record, with a larger volume
    • docker save -o xxx.tar image_name:tag
    • docker load -i xxx.tar

docker hub #

  1. docker login -u <username>
  2. docker search <image_name>
  3. docker push <username>/<image_name>
  4. dangling image: if the image is updated by official, and the tag is allocated to the new image, the old image will be called dangling image. Only display <none> in the docker images command.

containers #

  • docker ps -a list all containers
  • docker ps list running containers
  • docker stats search all the containers resource usage (CPU, memory, storage, network)
  • docker rename CONTAINER1 CONTAINER2
  • docker start | stop | restart | rm | top | inspect | kill | port | history CONTAINER
  • docker run -itd ubuntu:20.04 search and run a container (-i means stdio -t means pseudo-tty[1] -d means detach) == pull + create + start
    • eg. docker run -p 20000:22 --name my_docker_server -itd docker_images:1.0
    • For the -itd effection, you can refer to this blog[2].
  • docker attach CONTAINER
    • ⌃ + p and ⌃ + q which can detach the container
    • ⌃+d which can close and exit the container(exit; then the container will be stopped)
  • docker logs -f CONTAINER -f means follow, you can see the logs in real time
  • docker cp xxx CONTAINER:xxx
  • docker exec CONTAINER COMMAND
    • eg docker exec -it container_name bash
    • docker exec -it container_name /bin/bash if your garrison program is sshd(which is not accept input) not the bash, then you should use this command to substitute it. (Recommend, exit; the container will not be stopped)
    • You can also use docker run -it container_name /bin/bash specific the shell to enter the container.
  • docker update CONTAINER --memory 500MB
  • docker container prune remove all stopped containers
  • docker commit container_name image_name:tag Package the container as an image.(Not recommend use to build image, can use as a snapshot of the container)

Docker volume #

The volume will not be deleted when the container is deleted. Volume can be shared between containers.

  • docker volume create VOLUME create a volume
    • docker run --mount source=VOLUME,target=/webapp option to specify the volume
  • docker volume ls list all volumes
  • docker volume rm VOLUME remove the volume
  • docker volume prune remove all unused volumes
  • docker volume inspect VOLUME inspect the volume
  • docker rm -v CONTAINER remove the container and the volume

Besides, you can also mount the host directory to the container. The host directory path must be absolute path.

docker run -d -P \
    --name web \
    --mount type=bind,source=/src/webapp,target=/opt/webapp[,readonly] \
    training/webapp \
    python app.py

For the detail of build docker image, you can refer to the tips about dockerfile.

kill the process directly #

ps auxw | grep $(docker container ls | grep containername | awk '{print $1}') | awk '{print $2}'

Related readings


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