Compose stacks

A compose stack is an application made of several containers, described by a docker-compose.yml. It comes either from a pasted file or from a Git repository that has one at its root.

You don’t need to write a special compose file. The one that works on your laptop works on Quasar.

On every deployment, Quasar writes an adapted copy named docker-compose.quasar.yml next to the original, and runs that copy. In it:

• the service that serves the site gets the Traefik routing labels,
• that service is attached to the traefik-net network,
• host bindings on ports 80 and 443 are removed, because Traefik uses them for every application.

The original file is never modified, and neither is your repository.

The Routing section of the application’s page shows which service is routed, on which port, and what was changed.

Quasar never guesses from service or image names. It picks, in this order:

1. the service that published host port 80 or 443;
2. otherwise, the service the rest of the stack sits behind: it depends_on others, and nothing depends on it;
3. otherwise, the only service offering the port configured for the application;
4. otherwise, the only service in the file.

If none of these rules gives a single answer, Quasar routes nothing. Pick the service yourself in the Routing section, then redeploy.

YAML anchors and merge keys (&anchor, <<: *defaults) are supported.

Host ports other than 80 and 443 are kept: a stack may need to expose a database or a game server on purpose.

If the compose file already has traefik.* labels, Quasar runs it exactly as written and adds nothing. As a consequence, password protection set in Quasar is not applied.

Remove the labels from the file to let Quasar handle the routing.

When a repository has both a compose file and a Dockerfile, Quasar uses the compose file by default.

If the compose file is only for local development, open the Build section of the application and choose Dockerfile, then redeploy. Switching removes the containers from the other mode but keeps their volumes.

The CPU and memory limits of the application form don’t apply to stacks. Set them per service in the compose file, with deploy.resources.limits.