Version details: Cloudmin Pro 8.3, Webmin 1.770
I have two hosts, murder and swarm, on which I host VMs. murder is running cloudmin. swarm is configured as a slave DNS server for the cloudmin domains.
I finally thought it might be a good idea to have a backup cloudmin host, so I set up swarm per the documentation as a cloudmin replica. Doing this process broke the fact that swarm was set up as a DNS slave server. Additionally, the "List Managed Systems" function against the cloudmin replica did not show any of the hosts for murder, although I did see that their configs had been replicated over in /etc/webmin/servers. I assume this is what the docs mention about the replication behavior when a cloudmin master is also hosting VMs.
I decided that I didn't like that set up, so removed cloudmin from swarm and fired up a KVM guest (aerie) on another physical host and had that become a replica of murder. Now, when I look at "List Managed Systems" on aerie, I see all of the instances. However, all of the ones hosted on murder say that they're hosted on aerie. Is this the expected behavior? Is it a best practice to have the cloudmin master (and replicas) on nodes that do not host any VMs?
Comments
Submitted by JamieCameron on Sat, 12/26/2015 - 20:37 Comment #1
Also, you may be running into the limitation of cloudmin replication when it the master is itself a VM host. It doesn't really make sense to have a replica in this case, because if the master system fails you would still lose VMs hosted on it.
Submitted by mlbarrow on Sat, 12/26/2015 - 22:50 Comment #2
Yes -- I understand the folly in that particular failure scenario. At the same time, I want things to look "nice". That being said, it sounds like the right thing from the standpoint of the management tool not looking weird would be to have it be isolated from the VM hosting machines. Obviously, this would create another point of failure in that this other machine would need to be up and running in order to manage VMs.
Thoughts?
Submitted by JamieCameron on Sun, 12/27/2015 - 23:21 Comment #3
Agreed, the current behavior is not optimal - we are working on this though, and I will update this ticket when improvements have been implemented.
The ideal Cloudmin setup for maximum redundancy would be to have the primary master, replica master and VM hosts be completely separate physical systems. However, in a pinch the replica could be another of the VM hosts.