Hi Midhunlal,

If your infrastructure services which should have minimal 3 nodes to form a quorum (like RabbitMQ and Mariadb and potentially some additional services If you are using some)
are running on controller nodes, you should have 3 controllers.

If you are HW limited, you also can have 2 nodes, but you can expect some form of split-brain in future.
If you still will have only 2 controllers, 

1. you should consider to use mariadb arbitrator for mariadb (member of quorum, not replicating data) which should be in some third location
2. Handle cluster_partition_handling in rabbitmq config (probably autoheal for two nodes)

Next you have to prepare some loadbalancer (haproxy, nginx , apache ? ), some HA solution (keepalived ? with virtualiP ) and add that two controllers as backends.
Edit endpoints to point to HA virtualIP address of loadbalancer

That's  minimal I think.

Michal Arbet
Openstack Engineer

Ultimum Technologies a.s.
Na Poříčí 1047/26, 11000 Praha 1
Czech Republic

+420 604 228 897 
michal.arbet@ultimum.io
https://ultimum.io



pá 20. 8. 2021 v 10:57 odesílatel Midhunlal Nb <midhunlaln66@gmail.com> napsal:
Hi Mohammed,
If you have any documents  or procedure for this set up ,then please share with me.

On Fri, Aug 20, 2021, 10:35 AM Mohammed Naser <mnaser@vexxhost.com> wrote:
Most openstack services are stateless but a lot of the infrastructure services like RabbitMQ and MariaDB form a quorum therefore need at least 3 replicas or you might have a bad time if an outage occurs

On Fri, Aug 13, 2021 at 10:36 PM Midhunlal Nb <midhunlaln66@gmail.com> wrote:
Hi team,
I have a rocky installed openstack environment  and it is working fine.In my set up I have;

1 controller node,2 compute nodes  and 1 storage node.

Now we are planning to add 1 more controller node as standby.Is it possible to add 1 more controller node in existing set up? if it is possible ,anyone please share the procedure.


Thanks & Regards
Midhunlal N B
+918921245637

--
Mohammed Naser
VEXXHOST, Inc.