If you install Docker on your Synology system, you will get two executables on the command line: docker, and docker-compose but no docker compose plugin! Thankfully, we can quickly and easily fix that.

While there are no official Synology instructions on this, we can follow the generic Linux x86_64 instructions from Docker's website for this:

Install the Compose plugin

Download and install Docker Compose on Linux with this step-by-step handbook. This plugin can be installed manually or by using a repository.

Docker Documentation

Installation Quick Steps

This will install the docker compose plugin on a single user. You can modify this command to install for all users using the official instructions linked above. Below are the quick commands you can simply copy and paste to get it for your user.

First SSH in into your Synology NAS. Then simply copy and paste the commands below. You can do it one line at a time or all at once too.

DOCKER_CONFIG=${DOCKER_CONFIG:-$HOME/.docker}
mkdir -p $DOCKER_CONFIG/cli-plugins
curl -SL https://github.com/docker/compose/releases/download/v2.17.2/docker-compose-linux-x86_64 -o $DOCKER_CONFIG/cli-plugins/docker-compose
chmod +x $DOCKER_CONFIG/cli-plugins/docker-compose

and then you can test that it works by doing:

docker compose version

At the time of writing, I was able to use the above commands and the output shows:

peter@home_office_nas:~$ docker compose version
Docker Compose version v2.17.2

Install for all users

Here is the command modified to allow docker compose on your Synology for all users (who have access rights, of course):

DOCKER_CONFIG=${DOCKER_CONFIG:-/usr/local/lib/docker}
mkdir -p $DOCKER_CONFIG/cli-plugins
curl -SL https://github.com/docker/compose/releases/download/v2.17.2/docker-compose-linux-x86_64 -o $DOCKER_CONFIG/cli-plugins/docker-compose
sudo chmod +x /usr/local/lib/docker/cli-plugins/docker-compose