Comment 0 for bug 1834403

Trying to deploy a custom image that is still deploying, gives a non-specific error:
2019-06-27 12:08:01 maasserver.websockets.protocol: [critical] Error on request (24) machine.action: Deployment operating system custom win2016-canonical-virtio is unavailable.

The same non-specific error appears in the Web UI.

Ideally the error would indicate why the deployment is not available. This happened when trying to deploy a freshly imported custom image (5GB) - it takes 5-10 minutes to sync at least on my testing setup and could be an easy place for new users to get stuck.