operator remove: with multiple revision fails with Operator controller is not installed

[shamsher31]

Ref: https://istio.io/latest/docs/setup/install/operator/#uninstall

If multiple revision of Istio is installed with the operator. During the previous revision cleanup using the following command.

kubectl delete istiooperators.install.istio.io -n istio-system example-istiocontrolplane

The operator remove command with revision is not able to find a controller for the operator and throws the following error.

istioctl operator remove --revision 1-8-1
Operator controller is not installed in istio-operator namespace (no Deployment detected).
Aborting, use --force to override.

Found this issue while debugging https://github.com/istio/istio/issues/31304

[shamsher31]

cc: @morvencao

[morvencao]

If I recall correctly, the 1-8-1 operator deployment was deleted by the another istio operator. It was deleted during the pruning process after end-users delete the old IOP CR. I raised a PR to fix that, see: https://github.com/istio/istio/pull/30949

[tanjunchen]

@morvencao In this case, you can try to delete the new iop, and you find that the iop is deleted, but the istio cluster is not deleted. An error occurred during the synchronization phase of the istio operator. see API server conflict during finalizer removal, retrying. https://github.com/istio/istio/pull/30949 will fix it?

[morvencao]

In this case, you can try to delete the new iop, and you find that the iop is deleted, but the istio cluster is not deleted.

Haven't try this case, you delete new IOP to rollback?

[tanjunchen]

@morvencao
no, I just want to uninstall the istio cluster. you can try to do this.