Created a cluster, now can't leave it, what should I do?

SteveSteve

New Member
Jan 3, 2025
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Hi,

I have three PVE hosts, each with a dozen or so guests, and when playing around with Proxmox Datacenter Manager I noticed that I can migrate virtual machines from one to another, seemingly if they're in a cluster, so I thought "sure, I'll cluster these things and move an unimportant guest from pve1 to pve2 to pve3 to learn how that works"

Anyway, I created a cluster on pve1, then went to join it on pve2 and learned I couldn't, because one (or either?) of those already has guest VMs. All of my devices already have guest VMs. I can't find a way in the GUI to leave the cluster, and when I try to remove myself in the command line with pvecm it says I can't remove myself from my cluster that consists of only myself.

What should I be doing to "fix" this and stop being in a cluster of one node?

If I take backups (within Proxmox) of my guests, can I remove the guests and then restore the backups into a "new" guest?
 
You most certainly can.
OK, in that case maybe I'll just take backups of my guests, remove my guests, then get all 3 nodes into a cluster while they're guestless, and finally restore the guests.

I haven't used Proxmox backup yet, my guests are backed up mostly with Veeam agents or Veeam B&R, and I didn't know if deleting a guest also deleted backups of that guest.
 
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OK, in that case maybe I'll just take backups of my guests, remove my guests, then get all 3 nodes into a cluster while they're guestless, and finally restore the guests.
You only need to remove guests on the node you are trying to join to the cluster, (not pve1 in your case).

See here.


I haven't used Proxmox backup yet, my guests are backups up mostly with Veeam agents or Veeam B&R, and I didn't know if deleting a guest also deleted backups of that guest.
Make regular Proxmox backups for this.
 
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You only need to remove guests on the node you are trying to join to the cluster, (not pve1 in your case).
Well that's good to know, because pve1 is where all my "big" VMs are, and pve2 and pve3 probably has maybe 10GB worth of VMs between them compared to the 10TB on pve1. Thanks!

edit: I've made backups on pve2, and joined it to the cluster successfully I think, but now I seem to have the same issue as this thread.

When trying to restore the backups I made it says "could not activate storage 'local-zfs', zfs error: cannot import 'rpool': no such pool available (500)", but I don't actually understand what the other thread is saying is a solution to that.
 
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You should restore the backup (I'm guessing you are doing it on pve2) to a locally available storage, or on a shared storage that is also available on that node.
 
You should restore the backup (I'm guessing you are doing it on pve2) to a locally available storage, or on a shared storage that is also available on that node.
pve2 seems to have no storage anymore after joining the cluster.

Before joining cluster pve1 had "local" and "local-zfs", and pve2 also had "local" and "local-zfs", which were just the default names created during OS installation, but I was assuming these names were just "cosmetic" and don't impact anything functionality wise. Do the storage pools on each cluster member need different names or anything like that?

edit: I must just not understand how to properly set up the cluster, I fiddled around with 3 spare workstations, installed PVE on each, created a cluster on one and joined from the others, whether I'm using zfs or ext4 or whatever other filesystem after multiple repeated PVE installs, on every cluster joiner I always "lose" my storage immediately when joining the cluster. I'm guessing there's some other "thing" I need to do that I don't know what it is, and that's fine, I don't actually need replication or high availability or anything like that for my use case, I just thought logging in to 1 webui for my 3 hosts would be neat instead of logging in to 3 webuis :)

edit again: googling my problem found threads on this board that taught me how to reconfigure my storage, thanks @gfngfn256 @fiona and @fabian
 
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