Docker Cheat Sheet
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Dockerfile
A Dockerfile is a script used to build Docker images. It consists of a series of commands:
FROM
FROM image_name:tag
Description: Specifies the base image used to build the new image.
RUN
RUN command
Description: Executes a command in the new image’s filesystem during the build process.
CMD
CMD command
Description: Specifies the default command to run when a container is launched from the image.
WORKDIR
WORKDIR /path/to/directory
Description: Sets the working directory for subsequent instructions.
COPY
COPY source destination
Description: Copies files or directories from the host system into the image.
ADD
ADD source destination
Description: Similar to COPY, but can also extract tarballs or fetch URLs.
EXPOSE
EXPOSE port
Description: Informs Docker that the container listens on specific network ports at runtime.
ENV
ENV key=value
Description: Sets environment variables in the image.
ENTRYPOINT
ENTRYPOINT command
Description: Configures the container to run as an executable.
ARG
ARG variable_name
Description: Defines a variable that users can pass at build-time to the builder with the docker build command.
USER
USER username
Description: Sets the user the application will run as within the container.
Docker Registry
Login to a Docker registry:
docker login
Description: Logs in to a Docker registry interactively.
Logout from a Docker registry:
docker logout
Description: Logs out from a Docker registry.
Build an image from a Dockerfile:
docker build -t image_name .
Description: Builds a Docker image from a Dockerfile in the current directory.
Push an image to a Docker registry:
docker push image_name
Description: Pushes a Docker image to a Docker registry.
Docker Containers
Run a container interactively:
docker run -it image_name
Description: Starts a new container interactively using the specified image.
Run a detached container:
docker run -d image_name
Description: Starts a new container in detached mode (background).
Run a container with a custom name:
docker run --name custom_name image_name
Description: Starts a new container with a specific name.
Run a container with environment variables:
docker run -e \"VAR=value\" image_name
Description: Sets environment variables in the container.
Run a container and map ports:
docker run -p host_port:container_port image_name
Description: Maps a container port to a host port.
Run a container and mount a volume:
docker run -v /host/path:/container/path image_name
Description: Mounts a host directory into the container.
Stop a running container:
docker stop container_id
Description: Stops a running container.
Start a stopped container:
docker start container_id
Description: Starts a stopped container.
Pause a running container:
docker pause container_id
Description: Pauses the execution of a container.
Unpause a paused container:
docker unpause container_id
Description: Resumes a paused container.
Restart a container:
docker restart container_id
Description: Restarts a running or stopped container.
Attach to a running container:
docker exec -it container_id /bin/bash
Description: Attaches to a running container and opens a shell.
Remove a stopped container:
docker rm container_id
Description: Deletes a stopped container.
Remove a running container:
docker rm -f container_id
Description: Forces removal of a running container.
Show container resource usage:
docker stats container_id
Description: Displays live resource usage statistics of a container.
Show container logs:
docker logs container_id
Description: Displays logs from a container.
Copy files from/to a container:
docker cp /local/path container_id:/container/path
Description: Copies files between a container and the local filesystem.
Inspect a container:
docker inspect container_id
Description: Shows detailed information about a container.
Create a container without starting it:
docker create image_name
Description: Creates a new container without starting it.
Docker Networking
List networks:
docker network ls
Description: Lists all networks created on the Docker host.
Create a network:
docker network create my_network
Description: Creates a user-defined bridge network named ‘my_network’.
Inspect a network:
docker network inspect my_network
Description: Displays detailed information about the ‘my_network’ network.
Remove a network:
docker network rm my_network
Description: Removes the ‘my_network’ network.
Connect a container to a network:
docker network connect my_network container_name
Description: Connects a container to the ‘my_network’ network.
Disconnect a container from a network:
docker network disconnect my_network container_name
Description: Disconnects a container from the ‘my_network’ network.
Attach a container to multiple networks:
docker network connect my_network_2 container_name
Description: Attaches the container to an additional network ‘my_network_2’.
Create an overlay network:
docker network create --driver overlay my_overlay_network
Description: Creates a multi-host overlay network ‘my_overlay_network’.
Remove all unused networks:
docker network prune
Description: Removes all networks not used by at least one container.
Set up a custom bridge network:
docker network create --driver bridge --subnet=192.168.5.0/24 --gateway=192.168.5.1 my_custom_network
Description: Creates a custom bridge network ‘my_custom_network’ with specified subnet and gateway.
Limit container bandwidth on a network:
docker network create --driver bridge --subnet=192.168.5.0/24 --gateway=192.168.5.1 --opt \"com.docker.network.bridge.enable_icc=false\" my_secure_network
Description: Creates a secure bridge network ‘my_secure_network’ disabling inter-container communication.
Docker Volumes
List volumes:
docker volume ls
Description: Lists all volumes on the Docker host.
Create a volume:
docker volume create my_volume
Description: Creates a named volume named ‘my_volume’.
Inspect a volume:
docker volume inspect my_volume
Description: Displays detailed information about the ‘my_volume’ volume.
Remove a volume:
docker volume rm my_volume
Description: Removes the ‘my_volume’ volume.
Remove all unused volumes:
docker volume prune
Description: Removes all volumes not used by at least one container.
Mount a volume while running a container:
docker run -v my_volume:/path/in/container image_name
Description: Mounts the ‘my_volume’ volume to a specific path inside the container.
Mount a host directory as a volume:
docker run -v /host/path:/container/path image_name
Description: Mounts a directory from the host system into the container.
Specify volume driver:
docker volume create --driver my_driver my_volume
Description: Creates a volume using a specific volume driver ‘my_driver’.
Copy files from a container volume to the local host:
docker cp container_id:/path/in/container /local/host/path
Description: Copies files from a container volume to a directory on the local host.
Mount a read-only volume:
docker run -v my_volume:/path/in/container:ro image_name
Description: Mounts the ‘my_volume’ volume as read-only inside the container.
Mount a named volume with specific options:
docker run -v my_volume:/path/in/container:options image_name
Description: Mounts the ‘my_volume’ volume with specific options (e.g., read-write permissions).
Backup a volume to a tar archive:
docker run --rm -v my_volume:/data -v /backup:/backup ubuntu tar cvf /backup/my_volume_backup.tar /data
Description: Creates a tar archive of the ‘my_volume’ volume in the /backup directory.
Docker Compose
Create and start containers:
docker-compose up
Description: Builds, (re)creates, starts, and attaches to containers for a service.
Stop and remove containers:
docker-compose down
Description: Stops and removes containers, networks, volumes, and images created by ‘up’ command.
Build services:
docker-compose build
Description: Builds or rebuilds services defined in the docker-compose.yml file.
Start services:
docker-compose start
Description: Start services defined in the docker-compose.yml file.
Stop services:
docker-compose stop
Description: Stops services defined in the docker-compose.yml file without removing containers.
Restart services:
docker-compose restart
Description: Restarts services defined in the docker-compose.yml file.
Pause services:
docker-compose pause
Description: Pauses all services in the docker-compose.yml file.
Unpause services:
docker-compose unpause
Description: Unpauses all paused services in the docker-compose.yml file.
View service logs:
docker-compose logs
Description: Displays log output from services.
Scale services:
docker-compose scale service_name=num_of_instances
Description: Scale services to a specified number of instances.