Proxmox VE 6 - Removing cluster configuration

Jul 23, 2019
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I am new to Proxmox VE, still reading the docs, so please forgive my easy question.

I need to completely remove the cluster configuration from one of my servers. There are no nodes attached, no VMs, no containers.

I simply created the cluster by mistake, and now I would like to know the correct way to accomplish this under PVE 6.

I have found a dozen tutorials on the matter, but they are all about PVE 5.x and earlier, I don't know if they all apply to PVE 6 as well.

Thanks in advance for any help you will offer.
 

fabian

Proxmox Staff Member
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Jan 7, 2016
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Colin 't Hart

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Jan 20, 2017
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I have one machine with several virtual machines and containers. I added a new machine to this in a cluster config. Now I want to remove the second machine again. The second machine has no VMs or containers. Does the above apply? Will my first machine survive?
 

pgis

New Member
Jun 11, 2021
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This is a few years old at this point and if this counts as thread jacking let me know and I'll delete and start a new thread... it's just the same exact issue and I must have screwed up the fix somehow....

https://pve.proxmox.com/pve-docs/pve-admin-guide.html#pvecm_separate_node_without_reinstall minus the last few steps.

Code:
systemctl stop pve-cluster corosync
pmxcfs -l
rm /etc/corosync/*
rm /etc/pve/corosync.conf
killall pmxcfs
systemctl start pve-cluster

should do the trick.
I had a cluster with three nodes that were put in a cluster before their IPs had to be changed- I ran these cmds on each node hoping to roll back to a clean slate on each but it doesnt look like it worked.

after reading the link I ran the following on the nodes:
(with <node to delete> run 2 times for each, 2 other nodes)

Code:
systemctl stop pve-cluster
systemctl stop corosync

pmxcfs -l

rm /etc/pve/corosync.conf
rm -r /etc/corosync/*

killall pmxcfs

systemctl start pve-cluster

pvecm delnode <node to delete>

# ^this^ failed which the doc states is expected... so I ran

pvecm expected 1

pvecm delnode <node2>

this seemed to work from the WebGUI after cleaning up the /etc/pve/nodes directory but now when I try to rejoin to a new cluster the nodes now report:

Code:
detected the following error(s):

* authentication key '/etc/corosync/authkey' already exists
* corosync is already running, is this node already in a cluster?!
TASK ERROR: Check if node may join a cluster failed!

the primary node that I created the cluster on now reads "Standalone node - no cluster defined" but if I try to create a cluster I get:

Code:
cluster config '/etc/pve/corosync.conf' already exists (500)

I'd really like to avoid having to reinstall on all three nodes but at this point it might be the only way out of this problem that I know how to do...

thanks
 
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fabian

Proxmox Staff Member
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Jan 7, 2016
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if the steps above failed (although I am not sure how - the error messages you posted indicate you missed some of the steps?), a clean re-install might work best.
 
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pgis

New Member
Jun 11, 2021
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I thought I had it but then I accidentally chose the wrong NIC trying to rejoin to cluster and now I cant even log in... ‍♂️ loading the ISO onto a new flashdrive now...

thanks
 

appelsap

New Member
Aug 23, 2021
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Netherlands
I have one machine with several virtual machines and containers. I added a new machine to this in a cluster config. Now I want to remove the second machine again. The second machine has no VMs or containers. Does the above apply? Will my first machine survive?
Hey @Colin 't Hart , you've probably fixed this some other way. But for documentations worth, to remove a node from the cluster (which is NOT the master node) use the command below to remove nodes:

Code:
pvecm delnode <node-name>
 

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