We tested this out here at THG (a bit too late as we'd already deployed multiple regions). What we did was install a stretched galera cluster across multiple DCs with clustered proxysql fronting it so we could force writes to a single node. We then deployed keystone in each regions on top of this. We put keysone behind a geo-loadbalancer so each region would prefer talking to their local keystones and proxy sql would force writes to a single node in the stretched cluster avoiding issues with commit latency and deadlocks.
Horizon doesn't need to exist in a single region, it can exist in all regions as long as it has api connectivity to all regions endponts and the "global" keystone.
If you are using kolla we found it easier to have a specific deployment for keystone only and then each region had it's normal deployment but with a remote keystone. ________________________________ From: wodel youchi wodel.youchi@gmail.com Sent: 23 May 2023 14:02 To: OpenStack Discuss openstack-discuss@lists.openstack.org Subject: multi-region deployment
CAUTION: This email originates from outside THG
________________________________ Hi,
I have been reading about multi-region in openstack.
From my understanding, that keystone and horizon are shared and deployed only in the first region.
Is this correct? If yes, what happens if the first region goes down?
Regards.