Bug - Handling multiple IP addresses

[bcdiaconu]

Describe the bug
On my maas machine, I have 2 ip addresses, one is dynamically allocated so it will change on each reboot, and one that is static. The issues I'm facing are interconnected:

• postgresql configuration will listen to the dynamic address. Therefore, after reboot will not be able to listen on the already change IP. The config file is /etc/postgresql/14/main/postgresql.conf and the param is listen_addresses = '172.18.21.135, ::1, localhost'
• the regiond is configured to connect on the same dynamic ip address. Therefore, after reboot region controller will not be able to connect to postgresql database because the file /etc/maas/regiond.conf is configured to listen to the same replaced IP address.

Reproducing
Install canonical multipass on a windows host.
Create a new machine for installing maas.
Install maas on that particular machine.
Check in browser machine is working properly.
Stop and Start the machine for it to acquire new IP address.
Check in browser, it will no longer work.
Look into /etc/postgresql/14/main/postgresql.conf and the param is listen_addresses = '172.18.21.135, ::1, localhost'
Check the file /etc/maas/regiond.conf for line with content database_host: "172.18.21.135"
Check IP addresses by ip addr that the ip address was changed from 172.18.21.135 to another.

Observation
I observe there is maas_postgres_ipv4 variable that can be override but I do not see it used in the region controller installation.

[bcdiaconu]

I modified variable maas_postgres_primary_host_v4: "127.0.0.1" which did add this to the /etc/maas/regiond.conf as expected but it seems unsynchronized with the address in /etc/postgresql/14/main/postgresql.conf file