Run a Docker container
Ubuntu Core is made up entirely of snap packages. To run Docker containers, you need to have the Docker Engine installed as a snap.
This page assumes that you have installed Ubuntu Core via a pre-built image and would like to install the Docker Engine and run containers from the command line.
Install Docker Engine
After logging into the Ubuntu Core device, install the Docker Engine snap by running:
sudo snap install docker
Set up permissions
The installation should automatically connect the home interface to grant the Docker snap access to the non-hidden files in the user’s home directory.
The list of interface connections can be verified by running snap connections docker.
If the home interface hasn’t been auto-connected (such as on Ubuntu Core 16), connect it manually by running:
sudo snap connect docker:home
The
dockercommand only has access to your home directory. All files such asDockerfile,docker-compose.yamlor.envshould be inside home.
Add credentials for registry
If you use certificates to access a private registry, add these certificates into:
/var/snap/docker/current/etc/docker/certs.d/
Run the container
Now you can run a container like you would normally do it with Docker:
$ sudo docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
478afc919002: Pull complete
Digest: sha256:a26bff933ddc26d5cdf7faa98b4ae1e3ec20c4985e6f87ac0973052224d24302
Status: Downloaded newer image for hello-world:latest
Hello from Docker!
This message shows that your installation appears to be working correctly.
To generate this message, Docker took the following steps:
1. The Docker client contacted the Docker daemon.
2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
(arm64v8)
3. The Docker daemon created a new container from that image which runs the
executable that produces the output you are currently reading.
4. The Docker daemon streamed that output to the Docker client, which sent it
to your terminal.
To try something more ambitious, you can run an Ubuntu container with:
$ docker run -it ubuntu bash
Share images, automate workflows, and more with a free Docker ID:
https://hub.docker.com/
For more examples and ideas, visit:
https://docs.docker.com/get-started/
sudobecause it is not possible to add a user to the docker group on Ubuntu Core.
If you prefer using Docker Compose, that is also available:
sudo docker compose
Another way to run Docker containers on Ubuntu Core is via companion snaps. This means each container will be managed by its own snap package, containing its configuration. Such a package has a safer upgrade path, with rollback of config and data if something went wrong. To learn how to create such a companion snap, refer here.