Open Stack

Neutron would add a soft router that only knows the route to the metadata
service (and any other services you want your neutron private network vms
to be able to reach). This is not unique to the metadata service. Heat,
Trove, etc, all want this as a feature so that one can poke holes out of
these private networks only to the places where the cloud operator has
services running.

Excerpts from Fox, Kevin M's message of 2015-09-08 14:44:35 -0700:
> How does that work with neutron private networks?
> 
> Thanks,
> Kevin
> ________________________________________
> From: Clint Byrum [clint at fewbar.com]
> Sent: Tuesday, September 08, 2015 1:35 PM
> To: openstack-dev
> Subject: Re: [openstack-dev] [Neutron] cloud-init IPv6 support
> 
> Excerpts from Nir Yechiel's message of 2014-07-07 09:15:09 -0700:
> > AFAIK, the cloud-init metadata service can currently be accessed only by sending a request to http://169.254.169.254, and no IPv6 equivalent is currently implemented. Does anyone working on this or tried to address this before?
> >
> 
> I'm not sure we'd want to carry the way metadata works forward now that
> we have had some time to think about this.
> 
> We already have DHCP6 and NDP. Just use one of those, and set the host's
> name to a nonce that it can use to lookup the endpoint for instance
> differentiation via DNS SRV records. So if you were told you are
> 
> d02a684d-56ea-44bc-9eba-18d997b1d32d.region.cloud.com
> 
> Then you look that up as a SRV record on your configured DNS resolver,
> and connect to the host name returned and do something like  GET
> /d02a684d-56ea-44bc-9eba-18d997b1d32d
> 
> And viola, metadata returns without any special link local thing, and
> it works like any other dual stack application on the planet.
>