maas 2 adds multiple DNS entries for nodes

FWIW this will eventually work as it's returning the DNS in round robin, so the next retry of the hook should work fine. Regardless, this seems suboptimal to force it to have 2 hook runs to work.

I don't think we were aware that charms were relying on reverse DNS lookups to determine the hostname based on an IP address.

We were asked to do non-resolvable names for the interface-name-based PTR records, so that when a machine had multiple interfaces, it would show up nicely on a traceroute - but we did not add forward records for those entries, since it seemed like a bad idea for anything to rely on what could be an ephemeral name.

I think we should consider disabling the new feature which adds the interface-based names, at least for now.

This is a new feature of MAAS 2.0. This is something that we will not change in MAAS for 2.0. We did not introduce this behavior in MAAS 1.9 and reserved it for MAAS 2.0. MAAS 2.0 has many breaking changes that make the produce overall better. This is one of them, it allows an administrator to convert an IP address to the exact interface on a deployed machine.

This is actually a design change in MAAS to help address various of other issues in the field that were raised in the past. As a design change, MAAS won't fix this, but rather the charm will have to be updated to correctly parse hostnames from a machine when it has multiple DNS entries (which is a perfectly valid configuration).