Docker installation

Ubuntu

References

Official

• Install Docker Engine on Ubuntu
• Post-installation steps for Linux

Others

• Running Docker Containers as Current Host User

Remove all previous docker installation

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

Set up apt repository

1. Update apt and install some packages

   sudo apt-get update
   

   sudo apt-get install \
       ca-certificates \
       curl \
       gnupg \
       lsb-release
   

2. Add GPG key

   sudo mkdir -p /etc/apt/keyrings
   

   curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
   

3. Set up repository

   echo \
   "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" \
   | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
   

Install Docker Engine

1. Update the apt package index again

   sudo apt-get update
   

   sudo apt-get install docker-ce docker-ce-cli containerd.io docker-compose-plugin
   

2. Verify installation

   sudo service docker start
   

   sudo docker run hello-world
   

Manage Docker as a non-root user

1. Create docker group

   sudo groupadd docker
   

2. Add current user to the docker group

   sudo usermod -aG docker $USER
   

3. Activate changes to the groups

   newgrp docker
   

4. Verify changes -> able to run hello-world example without sudo

   docker run hello-world
   

If you encounter issues like

docker: Cannot connect to the Docker daemon at unix:///home/<user>/.docker/desktop/docker.sock. Is the docker daemon running?.

it is probably because the right docker context is not selected. Execute

export DOCKER_HOST=

and try again. If it works, include the line above in your .bashrc file. See How to Troubleshoot "Cannot Connect to the Docker Daemon" Error

Configure Docker to start on boot

To enable Docker to start on boot use the systemctl enable command:

sudo systemctl enable docker.service

sudo systemctl enable containerd.service

To disable docker starting at boot, use disable instead

sudo systemctl disable docker.service

sudo systemctl disable containerd.service