On 2020-11-30 14:45:52 +0000 (+0000), Stephen Finucane wrote: [...]
The two questions are unfortunately intertwined. The same information - 'instance.hostname' - is used both by cloud-init (via the metadata service/config drive) to initialize the instance name [1] and by neutron when attaching ports on a network with DNS integration [2]. Unless we decouple those, any change will affect both. [...]
Okay, then there was also a hidden additional question in there. Do people who set DNS(-like) names for their server instance names also rely on the hostname reported in the instance metadata for configuring the guest OS? In our case we don't, we explicitly set up /etc/hosts and such with configuration management rather than trusting something like cloud-init to get it correct. In our case I don't think we particularly care what "hostname" gets reported in the metadata, only that the instance name remains flexible. -- Jeremy Stanley