Designate leader stuck waiting: 'shared-db' incomplete

In testrun:
https://solutions.qa.canonical.com/testruns/testRun/623b7ed5-95d2-41d6-89c9-e83065b78eea
https://oil-jenkins.canonical.com/job/fce_build/516//console

Designate leader is stuck waiting:
-------------------------------------------
designate/0 active idle 0/lxd/3 10.246.165.100 9001/tcp Unit is ready
  designate-mysql-router/2 active idle 10.246.165.100 Unit is ready
  filebeat/51 active idle 10.246.165.100 Filebeat ready.
  hacluster-designate/2 active idle 10.246.165.100 Unit is ready and clustered
  landscape-client/51 maintenance idle 10.246.165.100 Need computer-title and juju-info to proceed
  logrotated/45 active idle 10.246.165.100 Unit is ready.
  nrpe/51 active idle 10.246.165.100 icmp,5666/tcp Ready (source version/commit cs-nrpe-...)
  public-policy-routing/28 active idle 10.246.165.100 Unit is ready
  telegraf/55 active idle 10.246.165.100 9103/tcp Monitoring designate/0 (source version/commit 26e531a)
designate/1* waiting idle 1/lxd/3 10.246.166.210 9001/tcp 'shared-db' incomplete
  designate-mysql-router/1 active idle 10.246.166.210 Unit is ready
  filebeat/41 active idle 10.246.166.210 Filebeat ready.
  hacluster-designate/0* active idle 10.246.166.210 Unit is ready and clustered
  landscape-client/43 maintenance idle 10.246.166.210 Need computer-title and juju-info to proceed
  logrotated/39 active idle 10.246.166.210 Unit is ready.
  nrpe/40 active idle 10.246.166.210 icmp,5666/tcp Ready (source version/commit cs-nrpe-...)
  public-policy-routing/13 active idle 10.246.166.210 Unit is ready
  telegraf/40 active idle 10.246.166.210 9103/tcp Monitoring designate/1 (source version/commit 26e531a)
-------------------------------------------

The mysql router reports 'ready'.

In the designate-central.log we see:
-------------------------------------------
[req-8a0d48cb-8a9b-443b-968c-0cefab0edbec - - - - -] Fixed interval looping call 'designate.heartbeat_emitter.HeartbeatEmitter._emit_heartbeat' failed: oslo_db.exception.CantStartEngineError: No sql_connection parameter is established
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/oslo_service/loopingcall.py", line 67, in func
    return f(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/designate/heartbeat_emitter.py", line 89, in _emit_heartbeat
    self.transmit(service_status)
  File "/usr/lib/python3/dist-packages/designate/heartbeat_emitter.py", line 109, in transmit
    api.update_service_status(admin_context, status)
  File "/usr/lib/python3/dist-packages/designate/rpc.py", line 238, in exception_wrapper
    return f(self, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/designate/central/service.py", line 2960, in update_service_status
    db_status = self.storage.find_service_status(
  File "/usr/lib/python3/dist-packages/designate/central/service.py", line 226, in storage
    self._storage = storage.get_storage(storage_driver)
  File "/usr/lib/python3/dist-packages/designate/storage/__init__.py", line 36, in get_storage
    return cls()
  File "/usr/lib/python3/dist-packages/designate/storage/impl_sqlalchemy/__init__.py", line 40, in __init__
    super(SQLAlchemyStorage, self).__init__()
  File "/usr/lib/python3/dist-packages/designate/sqlalchemy/base.py", line 70, in __init__
    self.engine = session.get_engine(self.get_name())
  File "/usr/lib/python3/dist-packages/designate/sqlalchemy/session.py", line 47, in get_engine
    facade = _create_facade_lazily(cfg_group)
  File "/usr/lib/python3/dist-packages/designate/sqlalchemy/session.py", line 38, in _create_facade_lazily
    _FACADES[cache_name] = session.EngineFacade(
  File "/usr/lib/python3/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 1289, in __init__
    self._factory._start(
  File "/usr/lib/python3/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 504, in _start
    self._setup_for_connection(
  File "/usr/lib/python3/dist-packages/oslo_db/sqlalchemy/enginefacade.py", line 527, in _setup_for_connection
    raise exception.CantStartEngineError(
oslo_db.exception.CantStartEngineError: No sql_connection parameter is established
-------------------------------------------

Crashdumps etc:
https://oil-jenkins.canonical.com/artifacts/623b7ed5-95d2-41d6-89c9-e83065b78eea/index.html