Docker Cheat Sheet

Docker provides the ability to package and run an application in an isolated environment called a container. The isolation and security allows you to run many containers simultaneously on a given host. Containers are lightweight and contain everything needed to run the application, so you do not need to rely on what is currently installed on the host. You can easily share containers while you work, and be sure that everyone you share with gets the same container that works in the same way.

General Commands

• Start the docker daemon

docker -d

• Get help with Docker. Can also use –help on all subcommands

docker --help

• Display system-wide information

docker info

Images

Docker images are a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.

• Build an Image from a Dockerfile

docker build -t [image_name]

• Build an Image from a Dockerfile without the cache

docker build -t [image_name] . –no-cache

• List local images

docker images

• Delete an Image

docker rmi [image_name]

• Remove all unused images

docker image prune

Docker Hub

Docker Hub is a service provided by Docker for finding and sharing container images with your team. Learn more and find images at Docker Hub Container Image Library | App Containerization

• Login into Docker

docker login -u [username]

• Publish an image to Docker Hub

docker push [username]/[image_name]

• Search Hub for an image

docker search [image_name]

• Pull an image from a Docker Hub

docker pull [image_name]

• Show history of Docker Image

docker history [image_name]

Container

A container is a runtime instance of a docker image. A container will always run the same, regardless of the infrastructure. Containers isolate software from its environment and ensure that it works uniformly despite differences for instance between development and staging.

• Create and run a container from an image, with a custom name:

docker run --name [container_name] [image_name]

• Run a container with and publish a container’s port(s) to the host.

docker run -p [host_port]:[container_port] [image_name]

• Run a container in the background

docker run -d [image_name]

• Start or stop an existing container:

docker start|stop [container_name] (or [container-id])

• Remove a stopped container: (add flag -f to remove a running container)

docker rm [container_name]

• Open a shell inside a running container:

docker exec -it [container_name] sh

• Fetch and follow the logs of a container:

docker logs -f [container_name]

• To inspect a running container:

docker inspect [container_name] (or [container_id])

• To list currently running containers:

docker ps

• List all docker containers (running and stopped):

docker ps --all

• View resource usage stats:

docker container stats

• Check stats for all containers:

docker stats --all

• View the running processes of a container:

docker top [container_name] (or [container_id])

-- Kill/Stop a running container:

docker kill [container_name] (or [container_id])

Networking

Networking in Docker refers to the ability for containers to connect to and communicate with each other, or to non-Docker workloads. Docker Networks are used to provide complete isolation for Docker containers.

• List all docker networks:

docker network ls

• Create a new Network:

docker network create [network_name]

• Connect a container to a network:

docker network connect [network_name] [container_name_or_id]

• Disconnect a container to a network:

docker network disconnect [network_name] [container_name_or_id]

• Remove a network:

docker network rm [network_name]

• Inspect a network:

docker network inspect [network_name]

Docker Compose

Docker Compose is a tool for defining and running multi-container applications. It is the key to unlocking a streamlined and efficient development and deployment experience.

• Build images:

docker-compose build

• docker-compose ps

docker-compose up

• Start containers in the background:

docker-compose up -d

• Stop and remove containers, networks, images, and volumes:

docker-compose down

• Stop running containers:

docker-compose stop

• Restart services:

docker-compose restart

• View service logs:

docker-compose logs

• View logs for a specific service:

docker-compose logs [service_name]

• Receive real-time events from containers:

docker-compose events

• List containers:

docker-compose ps

tip

By default, Docker Compose looks for a file named docker-compose.yml in the current directory. To specify a different file, use the -f flag:

docker-compose -f [custom-compose-file.yml] up