Active and standby controller nodes

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