uRWLFS

Useful tips & tricks to learn build and deploy your distributed applications easily to the cloud with Docker !

Want to improve this cheat sheet ? your PRs are welcome
With ❤️ by Ouadie LAHDIOUI

Install Docker

Check the installation guide for your platform

Try It Out

docker version
docker -v
docker info

Docker CLI basics

docker ps Shows all containers that are currently running
docker ps -a Shows all containers
docker images : See a list of all images on your system
docker rm <CONTAINER_ID> <CONTAINER_ID> Remove containers by id
docker rmi <IMAGES_ID> <IMAGES_ID> Remove images

Launching a container

docker run [options] [image] [process]
docker run hello-world Verify your system
docker run busybox Run a Docker container based on an image
docker run busybox echo "hello from busybox" Run an empty command and then exit
docker run --rm <CONTAINER_ID> Start a container automatically removed on stop
docker pull <IMAGE_ID> Fetches the busybox image from the Docker registry and saves it to your system
docker start <CONTAINER_ID> Restart a stopped container
docker stop <CONTAINER_ID> Stop a container

Run the container in interactive mode

docker run -it busybox sh Run a container in interactive mode (type exit to close)
docker run -t -i ubuntu /bin/bash launch an Ubuntu container and install what you want inside (Ex: apt-get update && apt-get install apache2)

Run the container in background

docker run -d <CONTAINER_ID>

Committing a container

docker commit <CONTAINER_ID> ouadie/busybox

Cleaning Up

docker rm <CONTAINER_ID> Remove a container
docker rmi <IMAGE_ID> Remove images
docker rm $(docker ps -a -q) Remove all containers
docker rmi $(docker ps -a -q) Remove all images

Build Images

docker build --tag myimage . Build an image from Dockerfile in current directory

Network access to 80

docker run -d -p 80:80 coreos/apache /usr/sbin/apache2ctl -D FOREGROUND

Go inside the container

docker exec -it <CONTAINER_ID> /bin/bash

Using the Docker registry

docker push coreos/apache Push to the public registry
docker push registry.example.com:5000/apache Push to a private registry

Using Docker Hub

Sign up for an account
Add a new repository, for example : https://hub.docker.com/r/ouadie/docker-cheatsheet
docker tag <IMAGE_ID> ouadie/docker-cheatsheet:latest|v1.0 Tag your docker image using
docker login Log in
docker push ouadie/docker-cheatsheet Push your image
docker search tomcat Search for an image

Dockerfile

Dockerfile allows developers to build Docker images automatically. It contains a list of commands.

It has the format :

INSTRUCTION arguments INSTRUCTION is not case-sensitive but convention says it ought to be uppercase to be easily distinguished from arguments.

Main commands :

FROM imageName[:version] imageName is the name of the Docker Image in docker hub. If the version is not specified, Docker takes the latest.
MAINTAINER creator Information about the creator of the image. (deprecated)
COPY <src> <dest> This command copies files or directories from src to the filesystem of the container at dest. If all files should be copied, src can be : "."
RUN <command> or RUN ["exec", "param1", "param2"] Commands are in shell form or exec form.
CMD <command> Commands in RUN are also in shell and exec form. In a Dockerfile, only one CMD instruction should be written, otherwise, only the last one will taken into consideration. It is the process to execute.
EXPOSE <port> [<port> ...] At runtime, the container will listen on the specified ports.
ENV <key> <value> ENV sets the environement variable key to the value value.

Build : docker build -t appName . Build Docker image using the Dockerfile in the root of the context.

docker build -f path/to/Dockerfile . Use -f to build a Docker image from anywhere in your file system.