Disabling dns plugin does not remove designate unit

[Hemanth Nakkina]

Disabling dns plugin does not remove designate unit.

snap-openstack: 2023.2/edge
designate charm: 2023.2/candidate

Designate unit is in error state.

$ juju status -m openstack designate
Model Controller Cloud/Region Version SLA Timestamp
openstack sunbeam-controller sunbeam-microk8s/localhost 3.2.4 unsupported 05:41:28Z

SAAS Status Store URL
grafana-dashboards active local micro1.project.serverstack/observability.grafana-dashboards
prometheus-scrape active local micro1.project.serverstack/observability.prometheus-scrape

App Version Status Scale Charm Channel Rev Address Exposed Message
designate error 1/0 designate-k8s 2023.2/candidate 10 10.152.183.101 no hook failed: "database-relation-broken"

Unit Workload Agent Address Ports Message
designate/0* error idle 10.1.224.122 hook failed: "database-relation-broken"

Offer Application Charm Rev Connected Endpoint Interface Role
ceilometer ceilometer ceilometer-k8s 14 1/1 ceilometer-service ceilometer provider
certificate-authority certificate-authority self-signed-certificates 57 1/1 certificates tls-certificates provider
cinder-ceph cinder-ceph cinder-ceph-k8s 45 1/1 ceph-access cinder-ceph-key provider
keystone keystone keystone-k8s 148 1/1 identity-credentials keystone-credentials provider
ovn-relay ovn-relay ovn-relay-k8s 50 1/1 ovsdb-cms-relay ovsdb-cms provider
rabbitmq rabbitmq rabbitmq-k8s 33 1/1 amqp rabbitmq provider

Unit logs:
----------

unit-designate-0: 05:37:54 ERROR unit.designate/0.juju-log database:154: Uncaught exception while in charm code:
Traceback (most recent call last):
  File "/var/lib/juju/agents/unit-designate-0/charm/./src/charm.py", line 480, in <module>
    main(DesignateOperatorCharm)
  File "/var/lib/juju/agents/unit-designate-0/charm/venv/ops/main.py", line 424, in main
    charm = charm_class(framework)
  File "/var/lib/juju/agents/unit-designate-0/charm/./src/charm.py", line 323, in __init__
    super().__init__(*args)
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/charm.py", line 718, in __init__
    super().__init__(framework)
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/charm.py", line 541, in __init__
    super().__init__(framework)
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/charm.py", line 100, in __init__
    self.relation_handlers = self.get_relation_handlers()
  File "/var/lib/juju/agents/unit-designate-0/charm/./src/charm.py", line 377, in get_relation_handlers
    return super().get_relation_handlers(handlers)
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/charm.py", line 762, in get_relation_handlers
    return super().get_relation_handlers(handlers)
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/charm.py", line 152, in get_relation_handlers
    db = sunbeam_rhandlers.DBHandler(
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/relation_handlers.py", line 270, in __init__
    super().__init__(charm, relation_name, callback_f, mandatory)
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/relation_handlers.py", line 89, in __init__
    self.set_status(self.status)
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/relation_handlers.py", line 103, in set_status
    elif self.ready:
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/relation_handlers.py", line 344, in ready
    data = self.get_relation_data()
  File "/var/lib/juju/agents/unit-designate-0/charm/lib/ops_sunbeam/relation_handlers.py", line 336, in get_relation_data
    return self.interface.relations[0].data[
  File "/var/lib/juju/agents/unit-designate-0/charm/venv/ops/model.py", line 1537, in __getitem__
    raise KeyError(
KeyError: 'Cannot index relation data with "None". Are you trying to access remote app data during a relation-broken event? This is not allowed.'
unit-designate-0: 05:37:55 ERROR juju.worker.uniter.operation hook "database-relation-broken" (via hook dispatching script: dispatch) failed: exit status 1