I had a quick question about Active-Active in cinder-volume and cinder-backup stable/stein and RBD driver, if anyone can help.

Using only the Ceph RBD driver for volume backends, is it required to run A-A cinder services with clustering configuration so that they form a cluster?

And, if so, is an external coordinator (redis/etcd/Consul) necessary, again only using RBD driver?

Best docs I could find on this so far were;

https://docs.openstack.org/cinder/latest/contributor/high_availability.html , 

I support more aimed at devs/contributoers than operators, but it's not 100% clear to me on these questions

Thanks,

Paul

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