Looks like we hit this with a newton deployment from landscape autopilot.

[from unit-rabbitmq-server-1.log]
2017-01-10 14:24:39 INFO config-changed Error: unable to connect to node 'rabbit@juju-b03454-1-lxd-1': nodedown
2017-01-10 14:24:39 INFO config-changed 
2017-01-10 14:24:39 INFO config-changed DIAGNOSTICS
2017-01-10 14:24:39 INFO config-changed ===========
2017-01-10 14:24:39 INFO config-changed 
2017-01-10 14:24:39 INFO config-changed attempted to contact: ['rabbit@juju-b03454-1-lxd-1']
2017-01-10 14:24:39 INFO config-changed 
2017-01-10 14:24:39 INFO config-changed rabbit@juju-b03454-1-lxd-1:
2017-01-10 14:24:39 INFO config-changed   * connected to epmd (port 4369) on juju-b03454-1-lxd-1
2017-01-10 14:24:39 INFO config-changed   * epmd reports: node 'rabbit' not running at all
2017-01-10 14:24:39 INFO config-changed                   no other nodes on juju-b03454-1-lxd-1
2017-01-10 14:24:39 INFO config-changed   * suggestion: start the node
2017-01-10 14:24:39 INFO config-changed 
2017-01-10 14:24:39 INFO config-changed current node details:
2017-01-10 14:24:39 INFO config-changed - node name: 'rabbitmq-cli-13458@juju-b03454-1-lxd-1'
2017-01-10 14:24:39 INFO config-changed - home dir: /var/lib/rabbitmq
2017-01-10 14:24:39 INFO config-changed - cookie hash: PQqnLl4zaYTm8d9gVBRhRQ==
2017-01-10 14:24:39 INFO config-changed 
2017-01-10 14:24:39 INFO config-changed Traceback (most recent call last):
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/config-changed", line 706, in <module>
2017-01-10 14:24:39 INFO config-changed     hooks.execute(sys.argv)
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/charmhelpers/core/hookenv.py", line 715, in execute
2017-01-10 14:24:39 INFO config-changed     self._hooks[hook_name]()
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/rabbit_utils.py", line 777, in wrapped_f
2017-01-10 14:24:39 INFO config-changed     f(*args, **kwargs)
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/charmhelpers/contrib/hardening/harden.py", line 79, in _harden_inner2
2017-01-10 14:24:39 INFO config-changed     return f(*args, **kwargs)
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/config-changed", line 659, in config_changed
2017-01-10 14:24:39 INFO config-changed     update_nrpe_checks()
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/config-changed", line 554, in update_nrpe_checks
2017-01-10 14:24:39 INFO config-changed     rabbit.create_vhost(vhost)
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/rabbit_utils.py", line 190, in create_vhost
2017-01-10 14:24:39 INFO config-changed     rabbitmqctl('add_vhost', vhost)
2017-01-10 14:24:39 INFO config-changed   File "/var/lib/juju/agents/unit-rabbitmq-server-1/charm/hooks/rabbit_utils.py", line 338, in rabbitmqctl
2017-01-10 14:24:39 INFO config-changed     subprocess.check_call(cmd)
2017-01-10 14:24:39 INFO config-changed   File "/usr/lib/python2.7/subprocess.py", line 541, in check_call
2017-01-10 14:24:39 INFO config-changed     raise CalledProcessError(retcode, cmd)
2017-01-10 14:24:39 INFO config-changed subprocess.CalledProcessError: Command '['/usr/sbin/rabbitmqctl', 'add_vhost', 'nagios-rabbitmq-server-1']' returned non-zero exit status 2
2017-01-10 14:24:39 ERROR juju.worker.uniter.operation runhook.go:107 hook "config-changed" failed: exit status 1


Although I can't tell from the rabbit logs if the service is ready to respond or not:

[from <email address hidden>]
=INFO REPORT==== 10-Jan-2017::14:24:32 ===
started TCP Listener on [::]:5672

=INFO REPORT==== 10-Jan-2017::14:24:32 ===
Server startup complete; 0 plugins started.

=WARNING REPORT==== 10-Jan-2017::14:25:32 ===
epmd does not know us, re-registering rabbit at port 25672


Logs from all the rabbitmq-servers attached.