[designate] Architecture help for designate on multi-region/multi-AZ deployments

Jean-Philippe Evrard openstack at a.spamming.party
Wed Mar 9 08:24:18 UTC 2022

Hello folks,

I currently have designate installed in a single region in a cloud.
Now we are thinking about the next steps: A multi-region designate for a simple use case: Bring your own domain, have A/AAAA records for your instances regardless of the region.
Side note: That requirement can be modified if what I am asking is impossible.

I didn't find anything in the ML, nor in the bug tracker [1] outside a neutron bug [2] (am I blind?). 
I had a look at the designate documentation, but there are no best practices for multi-region (or am I blind again?)
The only relevant part for integration with neutron is in [3], which is not region related.

I am looking for advice from designate experts here, to see what we can do.

Right now, we are thinking about two ways to deal with this:
A) Install a separate openstack with designate, and make all the regions's neutrons configuration point to a single designate. Neutron would work, designate would be simple to manage (as we have a single designate).
The downside here is the clear-cut separation of regions: I am afraid of how records are stored in the central designate, and if there won't be multi-tenancy issues (uuid could technically overlap, as different regions means different keystones here).
B) Install a designate in each region, with DNS servers in each region. We have strict region separation this way.
The downside is the user friendliness: A customer _can_ decide which region in  which the domain will be hosted. That means that we now need to worry about synchronizing region's state (if you have created a domain in that region, you can't do it elsewhere).

Am I misunderstanding/not seeing something obvious here?

Thank you in advance.

Jean-Philippe Evrard (evrardjp)

[0]: https://www.google.com/search?q=designate+multi+region+site%3Ahttp%3A%2F%2Flists.openstack.org%2Fpipermail%2Fopenstack-discuss%2F
[1]: https://bugs.launchpad.net/designate?field.searchtext=region
[2]:  https://review.opendev.org/c/openstack/neutron/+/684854/  
[3]: https://docs.openstack.org/neutron/latest/admin/config-dns-int-ext-serv.html 

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