Separate a node without re-installing

Stop Cluster Services

Firstly, stop all the cluster services.

$ systemctl stop pve-cluster
$ systemctl stop corosync

Reset PMXCFS Status

PMXCFS: Proxmox Cluster File System

  • Start the cluster filesystem in local mode:
$ pmxcfs -l
  • Delete the corosync config files.
$ rm /etc/pve/corosync.conf
$ rm /etc/corosync/*
  • Start the filesystem as a normal service.
$ killall pmxcfs
$ systemctl start pve-cluster

Remove Cluster Configuration Files

After killing all PMXCFS processes you must remove any remaining cluster config files for a proper re-join.

$ rm /var/lib/corosync/*
$ rm -r /etc/pve/nodes/NAMEOFPEERNODES
$ pvecm add $target_ring_0_address

source: https://pve.proxmox.com/pve-docs/pvecm-plain.html