To be clear, I think there are confusions in between three names :

#1 the instance display name

#2 the /etc/hostname

#3 the related /etc/hosts name

For #1, having a FQDN [1] is OK. Also, as it's an API field, we can't change it or it would need a new microversion.

For #2, as Jeremy said, in general you just have the short instance name, not the whole FQDN, so I think it's totally fine to strip the name after the first period (and AFAICT, that's why you see the short name already as the OS cuts it already)

For #3, you can *either* have short names or FQDNs but given we see problems with Designate, I'd be telling that we should also strip the name instead of having the whole FQDN, as anyway the domain is not verified by Nova.

-Sylvain

[1] By FQDN, I mean a name like "instance.tld" where "tld" is "domain[\..*]+"

On Thu, Dec 3, 2020 at 10:16 PM Thomas Goirand <zigo@debian.org> wrote:

On 11/30/20 12:51 PM, Stephen Finucane wrote:
> The other option is to strip all periods, or rather replace them with
> hyphens, when sanitizing the instance name. This is more predictable but breaks
> the ability to use the instance name as a FQDN. Such usage is something I'm told
> we've never supported, but I'm concerned that there are users out there who are
> relying on this all the same and I'd like to get a feel for whether this is the
> case first.

Hi,

We don't use Designate *yet*, but we're planning to. Using an FQDN for
the instance name is what we used to do so far. Even if that's not
something that *was* supported, it would IMO be desirable to support it,
at least in the future.

Just my 2 cents, hoping to help,
Cheers,

Thomas Goirand (zigo)