How can I use Multiple controller nodes
Hello, I just wanted to know if it is possible to use two controller nodes at the same time? (I found some documents mentioning galera but tbh I didn't understand exactly how it will be deployed) And if yes can you please help me. Thank you.
The official OpenStack documentation has little or no information about deploying HA. High-level: You need a load balancer that forwards requests to the services running on the controllers. You need an HA database, e.g. Galera. RabbitMQ is HA out of the box.
Most services are natively active-active, but Cinder-Volume is active-passive (only one Cinder-Volume can accept requests at the same time), and nova-consoleauth can only run once.
You should set up three controllers to avoid split-brain syndrome.
There used to be an official HA guide, but it has never been complete and is currently out of date and not published. Red Hat has a document about HA. Also google for openstack high availability.