Installer tui crash on updating 21.01.2 to 21.04.2 on Ubuntu 20.04.2 / s390x

[Frank Heimes]

While updating the Subiquity installer form 21.01.2 to 21.04.2 during a 20.04.2 LPAR/s390x installation I faced the following crash:

report saved to /var/crash/1623068068.856643915.ui.crash
Traceback (most recent call last):
  File "/snap/subiquity/2278/usr/bin/subiquity", line 33, in <module>
    sys.exit(load_entry_point('subiquity==0.0.5', 'console_scripts', 'subiquity-tui')())
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/cmd/tui.py", line 142, in main
    subiquity_interface.run()
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/client/client.py", line 326, in run
    super().run()
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquitycore/tui.py", line 338, in run
    super().run()
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquitycore/core.py", line 136, in run
    raise exc
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/ui/views/error.py", line 184, in _wait
    self.error_ref)
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/errorreport.py", line 436, in get_wait
    await self.client.errors.wait.GET(error_ref)
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/api/client.py", line 47, in impl
    meth.__name__, path, json=data, params=query_args) as resp:
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquitycore/contextlib38.py", line 171, in __aenter__
    return await self.gen.__anext__()
  File "/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/api/client.py", line 84, in make_request
    timeout=0) as response:
  File "/snap/subiquity/2278/lib/python3.6/site-packages/aiohttp/client.py", line 1117, in __aenter__
    self._resp = await self._coro
  File "/snap/subiquity/2278/lib/python3.6/site-packages/aiohttp/client.py", line 544, in _request
    await resp.start(conn)
  File "/snap/subiquity/2278/lib/python3.6/site-packages/aiohttp/client_reqrep.py", line 890, in start
    message, payload = await self._protocol.read() # type: ignore
  File "/snap/subiquity/2278/lib/python3.6/site-packages/aiohttp/streams.py", line 604, in read
    await self._waiter
aiohttp.client_exceptions.ServerDisconnectedError: Server disconnected
Connection to s1lp14 closed.

and at the console I've noticed:

"report saved to /var/crash/1623068073.935614824.ui.crash"
"Traceback (most recent call last):"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/client/client"
".py"", line 326, in run"
super().run()
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquitycore/tui.py"","
"line 338, in run"
super().run()
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquitycore/core.py"","
"line 136, in run"
"raise exc"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/client/client"
".py"", line 257, in start"
"status = await self.connect()"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/client/client"
".py"", line 240, in connect"
"status = await self.client.meta.status.GET()"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/api/cl"
"ient.py"", line 49, in impl"
"return serializer.deserialize(r_ann, await resp.json())"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/serial"
"ize.py"", line 131, in deserialize"
"return self._deserialize_attr(annotation, value, metadata, path)"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/serial"
"ize.py"", line 121, in _deserialize_attr"
"field, value[field.name], path))"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/serial"
"ize.py"", line 114, in _deserialize_field"
"field.type, value, field.metadata, path)"
"File ""/snap/subiquity/2278/lib/python3.6/site-packages/subiquity/common/serial"
"ize.py"", line 138, in deserialize"
"return getattr(annotation, value)"
"File ""/snap/subiquity/2278/usr/lib/python3.6/enum.py"", line 326, in __getattr_"
_
"raise AttributeError(name) from None"
"AttributeError: CLOUD_INIT_WAIT"

I'll attache a plain text file with some more details
as well as a tgz with the entire content of /var/crash and /var log

After reconnecting to the installer SSH session I was finally able to complete the installation (and the installer was on the updated level).

[Frank Heimes (fheimes)]

Retried today updating to latest/candidate and the snap update itself worked,
subiquity ui was (re-)started, but failed immediately after restart
and showed me a prompt (within the remaining of the ui).
Trying to run 'snap list subiquity' caused a crash then.
Sharing what I saw in my remote shell as well as a packages log/crash files ...

Manually reconnecting to the installer from remote via ssh after this allows to complete the installation based on the new installer.

[Frank Heimes (fheimes)]

With the release of 20.04.3, that includes subiquity 21.08.2, this is now obsolete.
(Even subiquity updated from 21.08.1 to a special build worked.)
Hence I'm closing this ticket as Fix Released.