DOCKER CHEAT SHEET 🐳⛴️📦🚀

• Names are identifiers for docker images, usually following the format [repository/]username/app
• Tags are labels that specify the version of an image, usually following the format image_name:version_nbr
  • The latest tag does not get automatically managed by Docker registries but must be manually maintained or automated using tools like GitHub Actions. It's only convention.

In the following guide VARIABLE should signify inputting variable of that type and [VARIABLE...] should signify that as many variables of that type may be passed.

GENERAL

➡️ docker version

Check docker version.

➡️ docker info

Provides info about Docker installation & containers & images.

➡️ docker inspect RESOURCE

Returns detailed info on containers, images, volumes, etc.

➡️ docker system prune

Removes stopped containers, unsued networks, dangling images, and build cache. More specific prune commands are available but not listed here.

➡️ docker system df

Shows Docker disk usage.

IMAGES

Lightweight, stand-alone, executable package. Filesystem snapshot with all dependencies & instructions needed to run.

➡️ docker images

Lists all Docker images on local machine.

➡️ docker pull [OPTIONS] IMAGE[:TAG|@DIGEST]

Downloads an image from a Docker registry like Docker hub, e.g. docker pull ubuntu:20.04.

➡️ docker build [OPTIONS] PATH | URL | -

Builds a Docker image from a Dockerfile in specified directory, e.g. docker build -t myapp:latest .. Defaults to latest tag if none is specified.

➡️ docker rmi [IMAGE...]

Deletes one or more images from local machine, e.g. docker rmi ubuntu:20.04.

➡️ docker tag SOURCE_IMAGE:SOURCE_TAG TARGET_IMAGE:TARGET_TAG

Adds an additional tag to an existing image, e.g. docker tag myapp:latest username/myapp:v1.0

➡️ docker push [OPTIONS] IMAGE_NAME:TAG

Pushes an image to a Docker registry, e.g. docker push username/myapp:v1.0

CONTAINERS

Running instance of an image as a blueprint.

➡️ docker ps

Shows all currently running containers. Add -a to include stopped ones. ps because of the Linux command that displays processes.

➡️ docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

Creates and starts a new container from an image, e.g. docker run -d -p 80:80 nginx

• -d or --detach will run the container in detached mode (in the background) and return to terminal prompt.
• -p 80:80 maps ports 80 of host and 80 of container together.

➡️ docker start CONTAINER

Starts a previously stopped container, e.g. docker start nginx.

➡️ docker stop CONTAINER

Stops a running container, e.g. docker stop nginx.

➡️ docker restart CONTAINER

Restarts a running container, e.g. docker restart nginx.

➡️ docker rm [CONTAINER...]

Deletes one or more containers, e.g. docker rm nginx.

➡️ docker stats

Displays real-time metrics for running containers.

➡️ docker exec [OPTIONS] CONTAINER COMMAND [ARG...]

Runs a command inside a running container, e.g. docker exec -it nginx bash opens up a bash shell in nginx.

docker cp [CONTAINER:]PATH [CONTAINER:]TARGET_PATH

Copies files between a container and the local filesystem. Don't specify container before a path to reference local file system. Copying from container to container directly is not supported.

➡️ docker commit [OPTIONS] CONTAINER IMAGE_NAME:TAG

Creates a new image from a container's changes, e.g. docker commit nginx username/nginx:v1.1

➡️ docker logs [OPTIONS] CONTAINER

Fetches the logs of a container in real-time, e.g. docker logs -f nginx.

• -f stands for follow - keeps the logs updating in real-time.

NETWORKS

Virtual network for containers. Handles communication between containers.

➡️ docker network ls

Lists all Docker networks on local machine.

➡️ docker network inspect NETWORK

Provides detailed information about a specific network.

➡️ docker network create [OPTIONS] NETWORK

Creates a new Docker network, e.g. docker network create server.

➡️ docker network rm NETWORK

Deletes a Docker network, e.g. docker network rm server.

VOLUMES

Persistent data storage seperate from a container's lifecycle.

➡️ docker volume ls

Lists all Docker volumes on local machine.

➡️ docker volume inspect VOLUME

Provides detailed information about a specific volume.

➡️ docker volume create [OPTIONS] VOLUME

Creates a new Docker volume, e.g. docker volume create shared_data

➡️ docker volume rm VOLUME

Deletes a Docker volume, e.g. docker volume rm shared_data

COMPOSE

Tool for defining and running multi-container Docker applications, as specified in a docker-compose.yml.
In older environments, the command may not be integrated yet, instead being docker-compose ....

➡️ docker compose up --build

Builds, starts and attaches to containers for a service.

• up executes starting instructions as defined in the same-directory file docker-compose.yml.
• --build ensures all Dockerfile or dependency changes are built into the images before starting the containers

➡️ docker compose down

Stops and removes containers, networks, volumes, and images created by docker compose up.

➡️ docker compose stop [SERVICE...]

Stops a specific docker service as started by docker compose up.

➡️ docker compose build

Builds or rebuilds services defined in docker-compose.yml.

➡️ docker compose ps

List containers related to the services defined in the docker-compose.yml.

➡️ docker compose logs

Shows logs from all services.