[openstack-dev] [nova] [neutron] Should we continue providing FQDNs for instance hostnames?
johnsomor at gmail.com
Tue Sep 5 15:41:47 UTC 2017
FYI, code in Octavia that checks for the extensions you could borrow:
On Mon, Sep 4, 2017 at 11:18 PM, Gary Kotton <gkotton at vmware.com> wrote:
> On 9/4/17, 3:47 PM, "Stephen Finucane" <stephen at that.guru> wrote:
> On Mon, 2017-09-04 at 11:51 +0000, Gary Kotton wrote:
> > On 9/4/17, 11:18 AM, "Stephen Finucane" <sfinucan at redhat.com> wrote:
> > > Nova has a feature whereby it will provide instance host names that cloud-
> > > init can extract and use inside the guest, i.e. this won't happen without
> > > cloud-init. These host names are fully qualified domain names (FQDNs) based
> > > upon the instance name and local domain name. However, as noted in bug
> > > #1698010 , the domain name part of this is based up nova's 'dhcp_domain'
> > > option, which is a nova-network option that has been deprecated .
> > >
> > > I've started work on a fix  that will allow us to retrieve this
> > > information from neutron instead, uncoupling us from this legacy option.
> > > However, some commentators have pointed out that this may not necessarily
> > > be what we want to do: a FQDN is a hostname and domain name, and using one
> > > as a hostname may not be that clever nor correct.
> > >
> > > My networking fu isn't strong enough to deliver a verdict so I'm hoping
> > > someone else can make my mind up for me: do we want to migrate this feature
> > > to neutron, or do we want to stop using FQDN and just use instance names?
> > Hi,
> > Your patch https://review.openstack.org/#/c/480616/ requires that neutron
> > expose the ‘DNS Integration’ extension be support by neutron and the relevant
> > networking plugin. If it does not then will be a regression and things will
> > not work.
> > In addition to this that is per network and not global so there will also be
> > a regression for running instances if nova is updated.
> OK, so ultimately this isn't something we can rely on from neutron?
> [Gary] No, you can rely on it from Neutron – you just need to be aware that if the extension is supported then it can be used. If not then you should continue to use the existing configuration vaiable
> Does that
> mean we should abandon the idea of providing FQDN when using neutron? Mores to
> the original point, is there any reason we would want to/should use FQDN?
> [Gary] Yes, we should support this. Applications make use of this and hence the support
> > >  https://bugs.launchpad.net/nova/+bug/1698010
> > >  https://review.openstack.org/#/c/395683/
> > >  https://review.openstack.org/#/c/480616/
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