I've noticed this in the CI: terraform tries to create an ironic node after the API starts but before the built-in conductor is ready, resulting in the following traceback in the ironic pod on bootstrap:

2022-03-24 16:29:50.528 1 ERROR ironic.api.method [req-ef4b0bb8-2be1-4b99-bac6-d4732ecdb4e9 - - - - -] Server-side error: "Cannot use 'none' RPC to connect to remote conductor 172.22.0.2". Detail: 
Traceback (most recent call last):

  File "/usr/lib/python3.6/site-packages/ironic/api/method.py", line 42, in callfunction
    result = f(self, *args, **kwargs)

  File "/usr/lib/python3.6/site-packages/ironic/api/method.py", line 109, in inner_body
    return function(*args, **kwargs)

  File "/usr/lib/python3.6/site-packages/ironic/common/args.py", line 379, in inner_check_args
    return function(*args, **kwargs_next)

  File "/usr/lib/python3.6/site-packages/ironic/api/controllers/v1/node.py", line 2493, in post
    new_node, topic)

  File "/usr/lib/python3.6/site-packages/ironic/conductor/rpcapi.py", line 314, in create_node
    cctxt = self._prepare_call(topic=topic, version='1.36')

  File "/usr/lib/python3.6/site-packages/ironic/conductor/rpcapi.py", line 213, in _prepare_call
    % host)

ironic.common.exception.ServiceUnavailable: Cannot use 'none' RPC to connect to remote conductor 172.22.0.2


I don't know how to reproduce this issue on purpose, but I think the fix is quite simple: only start API after the conductor is started.