1. Proposed title of this feature request

Dedicated MariaDB Galera Cluster for each OpenStack Service
2. What is the nature and description of the request?

For large scale deployment of OpenStack, it's recommended to dedicate one Database Galera cluster for each OpenStack Service

This allows to : 

• Reduce the impact when a Galera cluster is down

• Allow intervention on smaller part of the infrastructure
• better distribute big number of requests

3. Why does the customer need this? (List the business requirements here)

The request is coming from a very strategic partner to our business in the UAE, they are the largest public cloud and service provider in their region.

This partner deployed a large scale deployment of RHOSO, with 900 compute nodes and big workload for the first cluster. He mentioned willing to achieve 1500 compute nodes for the second RHOSO cluster.

In their current Legacy Cloud, the partner has a configuration with one Database cluster by OpenStack service

4. List any affected packages or components.

• MariaDB Galera
• All OpenStack Services/Pods

5. References

On Upstream side, Large Scale SIG group has already done tests and is recommending  to split the Galera cluster into separate clusters, here [1]

 [1]: https://docs.openstack.org/large-scale/journey/configure/database.html

Another feedback, I know that OVH Cloud are dedicating a Galera cluster for the Keystone service.