Comment 26 for bug 1859656

The assumption from here was that this only appeared to be working due to:

a) Deploy = netboot + reboot from disk = working

but at the same time

b) Start = netboot (fail) + no fallback = fail

To get that from Maas UI we stopped the guest (it went down as expected).
Then from Maas we said "power on" again.

There on (b) it failed as maas didn't provide it with an install image.
If you track it in the console you see:

$virsh start vm1 --console
setlocale: No such file or directory
Domain vm1 started
Connected to domain vm1
Escape character is ^]
done
  Using IPv4 address: 192.168.122.102
  Using TFTP server: 192.168.122.1
  Bootfile name: 'boots390x.bin'
  Receiving data: 0 KBytes
  TFTP error: file not found: boots390x.bin
Trying pxelinux.cfg files...
  Receiving data: 0 KBytes
  Receiving data: 0 KBytes
Failed to load OS from network

Maas tries a few times as we see the guest flip between "shut off" and "paused" state.
But then fives up.

The super-TL;DR matching the current insights is:
- deploy s390x Maas-KVM @ s390x worked and still does
- poweroff/poweron s390x Maas-KVM @ s390x never worked and still does not

To fix the latter we either need
a) upstream to implement a fallback to the next boot mechanism
b) maas to modify the XML after deploy to boot from disk