It was previously set to extensions/v1beta1. I have discovered that when
the Deployment is created as a extensions/v1beta1, it causes the
existing pod to be killed immediately when doing a rolling update. When
the Deployment was created as apps/v1, a rolling update behaves as
expected: a new pod is created, and the old one is only terminated once
the new pod is ready to serve traffic.
The existing Deployment resource will need to be deleted and recreated:
kubectl delete deployment gitea-server
kubectl apply -f gitea-server.yaml
Applying the file without deleting it first will not fix the issue with
rolling updates. It will cause a short downtime