Install docker on debian the easy way¶

This is the easiest way to install docker and docker compose on debian.

Better yet docker updates can be done by rerunning the script mentioned or using apt upgrade etc

Assumes you followed Debian VM Install Instructions

Install Docker¶

Login as yourself

curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh
sudo systemctl enable docker
sudo systemctl start docker

No really thats it. Note the latest version of the script automatically installs the docker compose plugin. so no need to install python or old docker-compose python app.

Let your user run docker without sudo¶

The install script does not add you to the docker group. Until you add yourself, docker ps fails with a permission error on /var/run/docker.sock:

sudo usermod -aG docker $USER

Then log out and back in. Group membership only applies to new login sessions, so your current shell keeps failing until you reconnect.

id -nG        # docker should now be listed
docker ps     # should work with no sudo

Use -aG. Without -a, usermod replaces your supplementary groups, sudo included.

This is required if you manage the host remotely¶

A remote Docker context like this one runs docker system dial-stdio on the target over SSH:

docker context create mynode --docker host=ssh://user@mynode

There is no way to prefix that with sudo, so a remote context cannot drive a host where docker needs sudo. If you plan to manage the node from your workstation, this step is mandatory.

The same applies to anything else that talks to the daemon over SSH, including DOCKER_HOST=ssh://....

Know what you are granting¶

Membership of the docker group is equivalent to root on that host. Anyone in it can start a container that mounts the host filesystem and has full access to it. That is how the Docker socket works, and it is why the group is not populated for you.

On a machine where you already have full sudo, this grants nothing new: it only removes a password prompt.

If your stacks keep their data on a shared mount¶

Docker doesn't know it needs that mount. On the swarm VMs I make it wait for the mount and refuse to start against an empty one, see make docker wait for the mount. Set it up once the data is on the mount, because the check fails on an empty one.

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