Comment 30 for bug 1797581

I didn't see any guests crashing, instead they all just hang finding nothing to boot.

I reduced this to just qemu (for debugging later on) but it reliably breaks finding nothing from PXE.

Guest Console:
  iPXE (PCI 00:03.0) starting execution...ok
  iPXE initialising devices...ok
  iPXE 1.0.0+git-20180124.fbe8c52d-0ubuntu2.1 -- Open Source Network Boot Firmware
   -- http://ipxe.org
  Features: DNS HTTP HTTPS iSCSI NFS TFTP AoE ELF MBOOT PXE bzImage Menu PXEXT

  net0: 52:54:00:3b:72:0a using virtio-net on 0000:00:03.0 (open)
    [Link:up, TX:0 TXE:0 RX:0 RXE:0]
  Configuring (net0 52:54:00:3b:72:0a).................. No configuration methods
  succeeded (http://ipxe.org/040ee119)
  No more network devices

Corresponding command to start qemu:
#!/bin/bash
/usr/bin/qemu-system-x86_64 -name guest=horsea-kvm-pod-2047,debug-threads=on -machine pc-i440fx-bionic,accel=kvm,usb=off,dump-guest-core=off -m 2047 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -cpu kvm64 -rtc base=utc -no-shutdown -curses \
-chardev socket,id=charmonitor,path=/tmp/horsea-kvm-pod-2047.monitor.sock,server,nowait \
-mon chardev=charmonitor,id=monitor,mode=control \
-chardev stdio,mux=on,id=charserial0,logfile=/tmp/horsea-kvm-pod-2047.log \
-device isa-serial,chardev=charserial0,id=serial0 \
-drive file=/var/lib/uvtool/libvirt/images/d9658e2f-d4c7-4a55-8ecc-b216612fe410,format=raw,if=none,id=drive-virtio-disk0 \
-device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk0,id=virtio-disk0,serial=d9658e2f-d4c7-4a55-8ecc-b216612fe410 \
 \
-boot order=n,strict=on \
 \
-net bridge,br=virbr1,helper=/usr/lib/qemu/qemu-bridge-helper -net nic,model=virtio,macaddr=52:54:00:3b:72:0a

This is the mac that is also in the libvirt XML.
The bridge is the one served by MAAS and it seems there is just no PXE responding to it.

Since the two other guests as started by maas+libvirt hang just the same way it most likely is a general MAAS setup issue.
Please help me to get MAAS to reply the way you would usually expect it, to then be able to go on with debugging.