Comment 4 for bug 1999827

Added description but comment as well

As this patch https://bugs.launchpad.net/maas/+bug/1600259, it takes IPs reversely and generate zone file.

https://github.com/maas/maas/blob/0c069f0aafbb650928f6c8536debd0de79eb7484/src/maasserver/dns/zonegenerator.py#L399

e.g

assume there is one nic which has 172.16.116.131 as a primary IP.

after adding one more ip to the same nic, zone file refer to secondary IP instead of primary IP.

{<Domain: name=maas>: defaultdict(<class 'maasserver.models.staticipaddress.HostnameIPMapping'>, {'xtrusia.maas': HostnameIPMapping('pca68y', 30, {'172.16.116.131'}, 4, None, None), 'ens33.xtrusia.maas': HostnameIPMapping('pca68y', 30, {'172.16.116.254'}, 4, None, 3), 'lxdbr0.xtrusia.maas': HostnameIPMapping('pca68y', 30, {'10.69.50.1'}, 4, None, 3)}), <Subnet: 172.16.116.0/24:172.16.116.0/24(vid=0)>: defaultdict(<class 'maasserver.models.staticipaddress.HostnameIPMapping'>, {'xtrusia.maas': HostnameIPMapping('pca68y', 30, {'172.16.116.254'}, 4, None, None), 'ens33.xtrusia.maas': HostnameIPMapping('pca68y', 30, {'172.16.116.131'}, 4, None, 3), 'lxdbr0.xtrusia.maas': HostnameIPMapping('pca68y', 30, {'10.69.50.1'}, 4, None, 3)}), 'reverse': defaultdict(<class 'maasserver.models.staticipaddress.HostnameIPMapping'>, {'xtrusia.maas': HostnameIPMapping('pca68y', 30, {'172.16.116.254'}, 4, None, None), 'ens33.xtrusia.maas': HostnameIPMapping('pca68y', 30, {'172.16.116.131'}, 4, None, 3), 'lxdbr0.xtrusia.maas': HostnameIPMapping('pca68y', 30, {'10.69.50.1'}, 4, None, 3)})}

I printed info from code, xtrusia.maas had 172.16.116.131 in the beginning, but after I added 172.16.116.254, it is changed to later.