MAAS fails to startup when installed from deb package and vault is enabled

Since this execution: http://maas-integration-ci.internal:8080/job/maas-system-tests/1553/

The regiond start up fails with: PermissionError: [Errno 13] Permission denied: '/etc/maas/.regiond.conf.g0xzpof9.tmp'

maas-system-tests.1553/archive/system-tests/sosreport/sosreport-maas-system-maas-2022-12-05-ejmycbi/var/log/maas/regiond.log

Full Traceback:

2022-12-05 19:55:49 maasserver.eventloop_17006.master: [info] Starting eventloop
2022-12-05 19:55:49 maasserver.eventloop_17006.master: [info] Calling start_up to start region process
2022-12-05 19:55:51 maasserver.start_up: [info] Migrated DB credentials from local config to vault
2022-12-05 19:55:51 maasserver.start_up: [error] Error during start-up.
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/maasserver/start_up.py", line 135, in start_up
    yield deferToDatabase(inner_start_up, master=master)
  File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 244, in inContext
    result = inContext.theWork() # type: ignore[attr-defined]
  File "/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 260, in <lambda>
    inContext.theWork = lambda: context.call( # type: ignore[attr-defined]
  File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 117, in callWithContext
    return self.currentContext().callWithContext(ctx, func, *args, **kw)
  File "/usr/lib/python3/dist-packages/twisted/python/context.py", line 82, in callWithContext
    return func(*args, **kw)
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 857, in callInContext
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/twisted.py", line 203, in wrapper
    result = func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 726, in call_with_connection
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/maasserver/utils/__init__.py", line 176, in call_with_lock
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 771, in call_within_transaction
    return func_outside_txn(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/maasserver/utils/orm.py", line 574, in retrier
    return func(*args, **kwargs)
  File "/usr/lib/python3.10/contextlib.py", line 79, in inner
    return func(*args, **kwds)
  File "/usr/lib/python3/dist-packages/maasserver/start_up.py", line 206, in inner_start_up
    migrate_db_credentials_if_necessary(client)
  File "/usr/lib/python3/dist-packages/maasserver/start_up.py", line 61, in migrate_db_credentials_if_necessary
    with RegionConfiguration.open_for_update() as config:
  File "/usr/lib/python3.10/contextlib.py", line 142, in __exit__
    next(self.gen)
  File "/usr/lib/python3/dist-packages/provisioningserver/config.py", line 697, in open_for_update
    with cls.backend.open_for_update(filepath) as store:
  File "/usr/lib/python3.10/contextlib.py", line 142, in __exit__
    next(self.gen)
  File "/usr/lib/python3/dist-packages/provisioningserver/config.py", line 565, in open_for_update
    configfile.save()
  File "/usr/lib/python3/dist-packages/provisioningserver/config.py", line 506, in save
    atomic_write(
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/fs.py", line 134, in atomic_write
    temp_file = _write_temp_file(content, filename)
  File "/usr/lib/python3/dist-packages/provisioningserver/utils/fs.py", line 94, in _write_temp_file
    temp_fd, temp_file = tempfile.mkstemp(
  File "/usr/lib/python3.10/tempfile.py", line 480, in mkstemp
    return _mkstemp_inner(dir, prefix, suffix, flags, output_type)
  File "/usr/lib/python3.10/tempfile.py", line 395, in _mkstemp_inner
    fd = _os.open(file, flags, 0o600)
PermissionError: [Errno 13] Permission denied: '/etc/maas/.regiond.conf.g0xzpof9.tmp'