Reinstall a Cluster Node

sahostking

Well-Known Member
We want to setup a cluster again but find that one question we about puzzled with as per the documentation here:

As said above, it is critical to power off the node before removal, and make sure that it will never power on again (in the existing cluster network) as it is. If you power on the node as it is, your cluster will be screwed up and it could be difficult to restore a clean cluster state.

Now the question lets say we have a full cluster going and working well but we want to rebuild one of the nodes so we live migrate the VMS onto another existing node.
We then power off that node. Removed the disks which is currently SAS disks and place in SSD disks we want to use instead in a RAID configuration. Now the issue comes in that when we reinstall this node. It will have the same IP addresses and server name.

Will it break the cluster if we choose the same name and give it the same IPs again? or MUST we change both to something else?
 
Will it break the cluster if we choose the same name and give it the same IPs again? or MUST we change both to something else?

No, as you completely re-installed the node it has no knowledge about the cluster anymore, so you can join it again to the cluster.

The warning is for situations were a node is just powered off, the node is deleted on another node, and after a bit the old node is powered on again (by mistake or whatever), as it still has the cluster communication authentication key, and the old cluster configuration it thinks that its still part of the cluster, and tries to rejoin, which can cause issues for the "real" cluster.

But in your case that cannot happen. You just need to decided if you either:
* run a pvecm delnode <NODE> after it's offline
* re-join the new normally

or:

* keep the node in and force-join the node back after it was re-imaged

Both are basically the same thing, slight advantage over the first one could be the fact that for the new join you could use the web interface, whereas for the second you need to use the CLI - but as that's always one CLI usage it probably also doesn't matters :)
 

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