Installing Docker and Setting Permission

Every server I set up eventually needs Docker. There are a few ways to install it. Snap is one option but I avoid it because it adds a lot of overhead and snap packages have caused me issues before. There is also the convenience script that pipes a shell script directly into bash from the internet, which I am not comfortable running on production machines.

The right way is the official apt repository method from Docker’s own documentation. It takes a couple of extra steps but you get the latest stable version from a verified source and full control over updates.

The permissions step at the end is important and most guides skip explaining why. By default Docker runs as root. Every docker command requires sudo. That gets tedious and causes permission errors when containers try to write files to bind mounts. Adding your user to the docker group means you run everything without sudo. Just make sure you trust who else is in that group since docker group access is effectively root access on the host.

Installing Docker

1. Setup docker’s apt repo

    sudo apt-get update
    sudo apt-get install ca-certificates curl
    sudo install -m 0755 -d /etc/apt/keyrings
    sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
    sudo chmod a+r /etc/apt/keyrings/docker.asc
    echo \
    "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
    $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
    sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
    sudo apt-get update
   

2. Install Latest Docker and its dependencies

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

3. Create Docker group (Most likely already created)

   sudo groupadd docker

4. Add user to the group

   sudo usermod -aG docker $USER

5. Logout and Log Back in or restart or ..

   newgrp docker

This will ensure you will not need to run “sudo” everytime you run docker and also fixes most Permission error.

If you run into DNS issues inside containers after this setup, see Broken Docker DNS Due to Pi-hole — a common gotcha on systems that have previously run Pi-hole.