I did manage to deploy drone-server and drone-agent in a GKE Kubernetes cluster.
When I go to my http://drone.foobar.com/ I successfully go through the OAuth dance.
I am able to see all the git repositories in my BitBucket Server and I activated couple of repositories. In both repositories at least one branch has a .drone.yml file (e.g. master in one and develop in another).
However, I can not see any way in the UI to manually kick off the builds for these repos. A git push to these branches does not start a build.
I also don’t see any webhooks getting created in BitBucket Server - so that at least explains why git push is not triggering a build.
kubectl logs on the server and agent both look normal - no errors.