We are currently running a single location CloudStack deployment: - 1 Hardware firewall - 1 Mangement/Database Server - 1 NFS staging store (for S3 secondary storage) - Ceph RBD for primary storage - 4 Hypervisors - 1 Zone/Pod/Cluster
We are looking to expand our deployment to other datacenters, and I'm trying to determine the best way to go about it. The documentation is a bit lacking for multi-site deployments. Our goal for the multi-site deployment is to have a zone for each site (E.G. US East, US West, Europe) that our customers can use to deploy instances in their preferred geographic area. Since we don't want to have different accounts for every datacenter, I don't think using Regions makes sense for us (and I'm not sure what they're actually good for without keeping accounts/users/domains in sync). Right now I'm thinking our setup will be as follows: - Firewall, Management Server, NFS staging server, primary storage, and Hypervisors in each datacenter. - All Management servers will be on the same management network. - Management servers will be connected via site-to-site VPN links over WAN. - MySQL replication (Percona?) will be set up on the management servers. Having an odd number of servers to protect against split brain, and keeping redundant database backups. - One region (default) - One zone for each datacenter - Geo-enabled DNS to direct customers to the nearest Management server - Object storage for secondary storage across cloud. My primary concerns with this setup are: - I haven't really seen multi-site deployments details anywhere. - Potential for split-brain. - How will HA be handled (e.g., if a VPN link goes down and one of the remote management servers can't contact a host, will it try to initiate HA?) - This sort of goes along with the split brain problem. Are my assumptions here sound, or is there a standard recommended way of doing multi-site deployments? Any suggestions are much appreciated.
