Descobrimos que o pacote qemu-system estava faltando.
Recebi a seguinte mensagem ao criar uma máquina virtual no virt-manager:
Error launching manager: 'NoneType' object has no attribute 'get_default_storage_format'
Traceback (most recent call last):
File "/usr/share/virt-manager/virtManager/engine.py", line 889, in _do_show_create
self._get_create_dialog().show(src.topwin, uri)
File "/usr/share/virt-manager/virtManager/create.py", line 170, in show
self.reset_state(uri)
File "/usr/share/virt-manager/virtManager/create.py", line 393, in reset_state
self.addstorage.reset_state()
File "/usr/share/virt-manager/virtManager/addstorage.py", line 196, in reset_state
fmt = self.conn.get_default_storage_format()
AttributeError: 'NoneType' object has no attribute 'get_default_storage_format'
Descobrimos que o pacote qemu-system estava faltando.