Readme.md

Docker basics

Docker installation

Ubuntu

official Ubuntu installation guide: https://docs.docker.com/install/linux/docker-ce/ubuntu/

uninstall older version, if applicable

sudo apt-get remove docker docker-engine docker.io containerd runc docker-ce docker-ce-cli containerd.io

installation from Docker respositories

#update package index
sudo apt-get update
# install packages to allow apt using https repositories
sudo apt-get install apt-transport-https ca-certificates curl gnupg-agent software-properties-common
# add Dockers GPG key
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
# configure the STABLE repository
sudo add-apt-repository \
   "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
# ....and start the installation
sudo apt-get update && sudo apt-get install docker-ce docker-ce-cli containerd.io

Check the installation, by running a hello world container:
sudo docker run hello-world

Post-install steps to run docker without prefixing it with sudo

sudo groupadd docker
sudo usermod -aG docker $USER
# logout and login again

If you used docker via sudo docker before, you will run the following now:

sudo chown "$USER":"$USER" /home/"$USER"/.docker -R
sudo chmod g+rwx "$HOME/.docker" -R

Check without sudo, by running a hello world container:
docker run hello-world

Windows

For users with Windows 10 64-bit Pro or Enterprise or Education-version, use Docker Desktop as shown here:
https://docs.docker.com/docker-for-windows/install/

Users with Windows 10 Home, Windows pre-10 versions, use Docker Toolbox as shown here:
https://docs.docker.com/toolbox/toolbox_install_windows/

Docker Toolbox ships also Oracle VirtualBox as virtualization solution, thereby this package is huge (~ 1GB) and should just be used if there are no other possibilities to run Docker. Windows 10 Home users should think about enabling the builtin Linux subsystem and install Ubuntu there !!

Mac

Docker Desktop: for Mac hardware >2010 and MacOS >= 10.13
https://docs.docker.com/docker-for-mac/install/

Docker Toolbox: for Mac users that do not cover above criteria https://docs.docker.com/toolbox/toolbox_install_mac/

Docker base commands

# check version
docker version

# list images
sudo docker image ls
# delete an image
sudo docker image rm <image-id>    # where <image-id> is shown in output of "sudo docker image ls"

# list containers
sudo docker container ls [--all]
# delete a container
sudo docker container rm <container-id>    # where <container-id> is shown in the output of "sudo container ls --all"

# run a container
sudo docker run <image>
# run an ubuntu container, provide env variables and run command "env" within container to check for the variable provided
sudo docker run -e ENV_VAR1=myvalue1 ubuntu env | grep ENV_VAR

# run a plain nginx webserver, 
# with random port assignment on local port => port 80 in container
# giving it a name "my-nginx"
# start the container in the background: "-d"
sudo docker run --name my-nginx -P -d nginx

# get details of a container
sudo docker inspect <container name>
sudo docker logs <container name>

# search for e.g. "nginx" containers from public repo
sudo docker search nginx

First container creation

cat > Dockerfile <<EOF
FROM busybox
CMD echo "Hello world! This is my first Docker image."
EOF

docker build -t container-1 .

Interaction with Docker Hub

# login to Docker Hub
docker login

# create Dockerfile for sample Nginx container (built on Ubuntu)
cat > Dockerfile <<EOF
FROM ubuntu:latest
RUN DEBIAN_FRONTEND=noninteractive apt-get update
RUN DEBIAN_FRONTEND=noninteractive apt-get -yq install net-tools nginx
EXPOSE 80
ENTRYPOINT ["/usr/sbin/nginx", "-g", "daemon off;"]
EOF


# build your image
sudo docker build -t <your-dockerhub-name>/<your-docker-repo-name> .

# test your container locally
sudo docker run <your-dockerhub-name>/<your-docker-repo-name> .

# push it to your Docker repository
sudo docker push <your-dockerhub-name>/<your-docker-repo-name>