cant change netvm while old-netvm is not running

[xaki23]

Qubes OS release

4.1

Brief summary

if a netvm crashes (and can not be restarted), it seems to be not possible to change the netvm of a running appvm to a working netvm. bonus: the error message is very misleading.

Steps to reproduce

creating a netvm and an appvm using it, starting both:

[root@dom0 ~]# qvm-clone sys-firewall test-fw
[root@dom0 ~]# qvm-create -l red --property netvm=test-fw test-appvm
[root@dom0 ~]# qvm-start test-appvm

hard-stop the netvm, try to change the netvm of appvm, get non-helpful error:

[root@dom0 ~]# qvm-kill test-fw
[root@dom0 ~]# qvm-prefs test-appvm netvm sys-firewall
usage: qvm-prefs [--verbose] [--quiet] [--help] [--help-properties] [--hide-default] [--get] [--set] [--default] VMNAME [PROPERTY] [VALUE]
qvm-prefs: error: no such property: 'netvm'

restart old-netvm, try changing appvm-netvm again, works as expected:

[root@dom0 ~]# qvm-start test-fw
[root@dom0 ~]# qvm-prefs test-appvm netvm sys-firewall
[root@dom0 ~]# 

Expected behavior

able to change netvm on an appvm.

Actual behavior

getting told "no such property: 'netvm'"

Educated Guess

seeing how this depends on whether the old-netvm is running or not, it probably throws somewhere when trying to reconfigure the expected-to-be-running old-netvm, and the throw is caught by a many-layers-up catch that translates it to the generic "huh?" error.

(proactive note for AD"needsdiagnosis"W ... figuring out where exactly it pops is like 90% of the fix.)

[marmarek]

See journalctl in dom0, likely the exception message is there.

-- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab

[palainp]

I had the same issue, the journal says:

libvirtd[1766]: device not found: no device matching MAC address XX:XX:XX:XX:XX:XX found
Jul 04 16:07:46 dom0 qubesd[2404]: unhandled exception while calling src=b'dom0' meth=b'admin.vm.property.Set' dest=b'VMNAME'>
Jul 04 16:07:46 dom0 qubesd[2404]: Traceback (most recent call last):
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/api/__init__.py", line 288, in respond
Jul 04 16:07:46 dom0 qubesd[2404]:     response = await self.mgmt.execute(
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/api/admin.py", line 265, in vm_property_set
Jul 04 16:07:46 dom0 qubesd[2404]:     return self._property_set(self.dest,
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/api/admin.py", line 285, in _property_set
Jul 04 16:07:46 dom0 qubesd[2404]:     setattr(dest, self.arg, newvalue)
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/vm/__init__.py", line 494, in __set__
Jul 04 16:07:46 dom0 qubesd[2404]:     super().__set__(instance, vm)
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/__init__.py", line 262, in __set__
Jul 04 16:07:46 dom0 qubesd[2404]:     instance.fire_event('property-pre-set:' + self.__name__,
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/events.py", line 195, in fire_event
Jul 04 16:07:46 dom0 qubesd[2404]:     sync_effects, async_effects = self._fire_event(event, kwargs,
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/events.py", line 164, in _fire_event
Jul 04 16:07:46 dom0 qubesd[2404]:     effect = func(self, event, **kwargs)
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/vm/mix/net.py", line 457, in on_property_p>
Jul 04 16:07:46 dom0 qubesd[2404]:     self.detach_network()
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/vm/mix/net.py", line 346, in detach_network
Jul 04 16:07:46 dom0 qubesd[2404]:     self.libvirt_domain.detachDevice(
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib/python3.8/site-packages/qubes/app.py", line 103, in wrapper
Jul 04 16:07:46 dom0 qubesd[2404]:     return attr(*args, **kwargs)
Jul 04 16:07:46 dom0 qubesd[2404]:   File "/usr/lib64/python3.8/site-packages/libvirt.py", line 1343, in detachDevice
Jul 04 16:07:46 dom0 qubesd[2404]:     if ret == -1: raise libvirtError ('virDomainDetachDevice() failed', dom=self)
Jul 04 16:07:46 dom0 qubesd[2404]: libvirt.libvirtError: device not found: no device matching MAC address XX:XX:XX:XX:XX:XX

[marmarek]

Duplicate of #6493

[andrewdavidwong]

This appears to be a duplicate of an existing issue. If so, please comment on the appropriate existing issue instead. If anyone believes this is not really a duplicate, please leave a comment briefly explaining why. We'll be happy to take another look and, if appropriate, reopen this issue. Thank you.