Comment 5 for bug 1228223

One more use case to support for the rpc calls between c-bak and c-vol is that suppose we introduce many more new backends in running cinder with c-bak and c-vol. We will need to stop c-vol and restart it. But admins will not restart c-bak as they think the services are independent of each other and hence the new introduced backends will not be spawned in c-bak even if they start running in c-vol. This will cause backup to fail for new configured backends. In my view it requires that we have a centralized service for driver backends which can be contacted for different tasks.