SSL SYSCALL error: EOF detected

Right before that error, similar errors are reported in regiond.log on one unit (.32) due to disconnection from Postgres:

2023-09-30 02:40:37 provisioningserver.rpc.common: [critical] Unhandled failure dispatching AMP command. This is probably a bug. Please ensure that this error is handled within application code or declared in the signature of the b'GetControllerType' command. [infra3:pid=2038237:cmd=GetControllerType:ask=cf]
 Traceback (most recent call last):
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/internet/asyncioreactor.py", line 271, in _onTimer
     self.runUntilCurrent()
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/internet/base.py", line 991, in runUntilCurrent
     call.func(*call.args, **call.kw)
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 700, in errback
     self._startRunCallbacks(fail)
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 763, in _startRunCallbacks
     self._runCallbacks()
 --- <exception caught here> ---
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 857, in _runCallbacks
     current.result = callback( # type: ignore[misc]
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/protocols/amp.py", line 1138, in checkKnownErrors
     key = error.trap(*command.allErrors)
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/python/failure.py", line 451, in trap
     self.raiseException()
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/python/failure.py", line 475, in raiseException
     raise self.value.with_traceback(self.tb)
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 244, in inContext
     result = inContext.theWork() # type: ignore[attr-defined]
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/python/threadpool.py", line 260, in <lambda>
     inContext.theWork = lambda: context.call( # type: ignore[attr-defined]
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/python/context.py", line 117, in callWithContext
     return self.currentContext().callWithContext(ctx, func, *args, **kw)
   File "/snap/maas/30885/usr/lib/python3/dist-packages/twisted/python/context.py", line 82, in callWithContext
     return func(*args, **kw)
   File "/snap/maas/30885/lib/python3.10/site-packages/provisioningserver/utils/twisted.py", line 856, in callInContext
     return func(*args, **kwargs)
   File "/snap/maas/30885/lib/python3.10/site-packages/provisioningserver/utils/twisted.py", line 203, in wrapper
     result = func(*args, **kwargs)
   File "/snap/maas/30885/lib/python3.10/site-packages/maasserver/utils/orm.py", line 771, in call_within_transaction
     return func_outside_txn(*args, **kwargs)
   File "/snap/maas/30885/lib/python3.10/site-packages/maasserver/utils/orm.py", line 574, in retrier
     return func(*args, **kwargs)
   File "/usr/lib/python3.10/contextlib.py", line 78, in inner
     with self._recreate_cm():
   File "/snap/maas/30885/usr/lib/python3/dist-packages/django/db/transaction.py", line 207, in __enter__
     connection.set_au...

From postgresql logs, it seems indeed the region disconnected around that time:

023-09-30 02:40:36.138 UTC [159374] maas@maasdb LOG: could not receive data from client: Connection reset by peer

but I don't see anything in region logs that would indicate why that happens.

Is this an isolated case or has it been observed other times?

UP until now we've only seen this one time, but future occurrences could be found here: https://solutions.qa.canonical.com/bugs/2038346

SSL SYSCALL error is reported by PostgreSQL and there might be multiple reasons for that.

Moving it to Incomplete, as this was (and still is) just a single occurrence.

[Expired for MAAS because there has been no activity for 60 days.]