Docker cheat sheet

Check Version

• docker version shows which version of docker you have running.

Containers

Lifecycle

• docker create creates a container but does not start it.

• docker rename allows the container to be renamed.

• docker run creates and starts a container in one operation.

• docker rm deletes a container.

• docker update updates a container's resource limits.

Starting and Stopping

• docker start starts a container so it is running.

• docker stop stops a running container.

• docker restart stops and starts a container.

• docker pause pauses a running container, "freezing" it in place.

• docker unpause will unpause a running container.

• docker wait blocks until running container stops.

• docker kill sends a SIGKILL to a running container.

• docker attach will connect to a running container.

CPU Constraints

You can limit CPU, either using a percentage of all CPUs, or by using specific cores.

For example, you can tell the cpu-shares setting. The setting is a bit strange -- 1024 means 100% of the CPU, so if you want the container to take 50% of all CPU cores, you should specify 512:

docker run -it -c 512 agileek/cpuset-test

You can also only use some CPU cores using cpuset-cpus:

docker run -it --cpuset-cpus=0,4,6 agileek/cpuset-test

Note that Docker can still see all of the CPUs inside the container -- it just isn't using all of them.

Memory Constraints

You can also set memory constraints on Docker:

docker run -it -m 300M ubuntu:14.04 /bin/bash

Info

• docker ps shows running containers.

• docker logs gets logs from container.

• docker inspect looks at all the info on a container (including IP address).

• docker events gets events from container.

• docker port shows public facing port of container.

• docker top shows running processes in container.

• docker stats shows containers' resource usage statistics.

• docker diff shows changed files in the container's FS.

Import / Export

• docker cp copies files or folders between a container and the local filesystem.

• docker export turns container filesystem into tarball archive stream to STDOUT.

Import/Export container

Import a container as an image from file:

cat my_container.tar.gz | docker import - my_image:my_tag

Export an existing container:

docker export my_container | gzip > my_container.tar.gz

Executing Commands

• docker exec to execute a command in container.

Images

Lifecycle

• docker images shows all images.

• docker import creates an image from a tarball.

• docker build creates image from Dockerfile.

• docker commit creates image from a container, pausing it temporarily if it is running.

• docker rmi removes an image.

• docker load loads an image from a tar archive as STDIN, including images and tags (as of 0.7).

• docker save saves an image to a tar archive stream to STDOUT with all parent layers, tags & versions (as of 0.7).

Info

• docker history shows history of image.

• docker tag tags an image to a name (local or registry).

Load/Save image

Load an image from file:

docker load < my_image.tar.gz

Save an existing image:

docker save my_image:my_tag | gzip > my_image.tar.gz

Dockerfile

Instructions

• .dockerignore

• FROM Sets the Base Image for subsequent instructions.

• MAINTAINER (deprecated - use LABEL instead) Set the Author field of the generated images.

• RUN execute any commands in a new layer on top of the current image and commit the results.

• CMD provide defaults for an executing container.

• EXPOSE informs Docker that the container listens on the specified network ports at runtime. NOTE: does not actually make ports accessible.

• ENV sets environment variable.

• ADD copies new files, directories or remote file to container. Invalidates caches. Avoid ADD and use COPY instead.

• COPY copies new files or directories to container. By default this copies as root regardless of the USER/WORKDIR settings. Use --chown=<user>:<group> to give ownership to another user/group. (Same for ADD.)

• ENTRYPOINT configures a container that will run as an executable.

• VOLUME creates a mount point for externally mounted volumes or other containers.

• USER sets the user name for following RUN / CMD / ENTRYPOINT commands.

• WORKDIR sets the working directory.

• ARG defines a build-time variable.

• ONBUILD adds a trigger instruction when the image is used as the base for another build.

• STOPSIGNAL sets the system call signal that will be sent to the container to exit.

• LABEL apply key/value metadata to your images, containers, or daemons.

• SHELL override default shell is used by docker to run commands.

• HEALTHCHECK tells docker how to test a container to check that it is still working.

Registry & Repository

• docker login to login to a registry.

• docker logout to logout from a registry.

• docker search searches registry for image.

• docker pull pulls an image from registry to local machine.

• docker push pushes an image to the registry from local machine.

Volumes

Lifecycle

• docker volume create

• docker volume rm

Info

• docker volume ls

• docker volume inspect

Networks

Lifecycle

• docker network create NAME Create a new network (default type: bridge).

• docker network rm NAME Remove one or more networks by name or identifier. No containers can be connected to the network when deleting it.

Info

• docker network ls List networks

• docker network inspect NAME Display detailed information on one or more networks.

Connection

• docker network connect NETWORK CONTAINER Connect a container to a network

• docker network disconnect NETWORK CONTAINER Disconnect a container from a network

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https://github.com/wsargent/docker-cheat-sheet#dockerfile