Docker Cheat Sheet

Introduction

This is a cheat sheet created to help me “remember” the core commands of Docker. So in essence it is not supposed to have any explanations, just a central place to copy code. Bellow you can get the references, so you can find from where it all was taken. If you need to better understand and get more information about Docker,  like how to install and things like that, this is the place to go: https://docs.docker.com/

 

The Most Helpful Command

docker COMMAND --help # there is an universe here!!!!

 

A Dockerfile Example

# Use an official Python runtime as a parent image
FROM python:2.7-slim

# Set the working directory to /app
WORKDIR /app

# Copy the current directory contents into the container at /app
ADD . /app

# Install any needed packages specified in requirements.txt
RUN pip install --trusted-host pypi.python.org -r requirements.txt

# Make port 80 available to the world outside this container
EXPOSE 80

# Define environment variable
ENV NAME World

# Run app.py when the container launches
CMD ["python", "app.py"]

 

Basic Commands List

Create image using this directory’s Dockerfile

docker build -t friendlyhello .

Run “friendlyname” mapping port 4000 to 80

docker run -p 4000:80 friendlyhello

Same thing, but in detached mode

docker run -d -p 4000:80 friendlyhello

List all running containers

docker container ls

List all containers, even those not running

docker container ls -a

Gracefully stop the specified container

docker container stop <hash>

Force shutdown of the specified container

docker container kill <hash>

Remove specified container from this machine

docker container rm <hash>

Remove all containers

docker container rm $(docker container ls -a -q)

List all images on this machine

docker image ls -a

Remove specified image from this machine

docker image rm <image id>

Remove all images from this machine

docker image rm $(docker image ls -a -q)

 

Push and Pull Docker Images to and from Docker Hub Repository

The Docker Hub repository is the “Github” for your images. To be able to use it, first create a Docker account here.

Log in this CLI session using your Docker credentials

docker login -u your_docker_username -p password

Tag <image> for upload to registry

docker tag <image> username/repository:tag

Upload tagged image to registry

docker push username/repository:tag

Run image from a registry

docker run username/repository:tag

 

Moving Images from Host to Host with Export and Save

 

Saves a container’s running or paused instance (assuming we are in one) to a file

docker export defc | gzip > ubuntu.tar.gz

 

Importing the exported image

gzcat ubuntu.tar.gz | docker import - ubuntu-alice

Moving Using save

docker save ubuntu | gzip > ubuntu-golden.tar.gz

Loading in another Host

gzcat ubuntu-golden.tar.gz | docker load

 

References

https://blog.giantswarm.io/moving-docker-container-images-around/
https://docs.docker.com/get-started/part2/#build-the-app