Comment 20 for bug 1805799

If running from a 20.04 host and installing 2.9 with snaps you can do the following (running as root):

snap stop maas.supervisor
umount /snap/maas/10851
unsquashfs /var/lib/snapd/snaps/maas_10851.snap

apt-get install python3-pip

cd squashfs-root
pip3 install --root ${PWD} --prefix . proxmoxer

# vi lib/python3.8/site-packages/provisioningserver/drivers/power/registry.py
# add lines below as appropriate
from provisioningserver.drivers.power.proxmox import ProxmoxPowerDriver
ProxmoxPowerDriver(),

# vi lib/python3.8/site-packages/provisioningserver/drivers/power/proxmox.py
# make sure to add the can_probe attribute as appropriate
<driver content>

mv /var/lib/snapd/snaps/maas_10851.snap /var/lib/snapd/snaps/maas_10851.snap.orig
mv maas_10851.snap /var/lib/snapd/snaps/maas_10851.snap

chmod 600 /var/lib/snapd/snaps/maas_10851.snap
reboot