How to delete a cluster on Proxmox

One of the key features of Proxmox VE is its ability to create and manage clusters of nodes, which can be used to provide high availability and scalability.

However, it’s important to note that a Proxmox VE cluster requires a minimum of three nodes in order to function properly. Without at least three nodes, you may not be able to log in to the Proxmox VE GUI and make changes.

If you find yourself in a situation where you need to remove a node from a Proxmox VE cluster, there are several steps that you can follow to ensure a smooth and successful removal process. Login to node using ssh and run following commands:

systemctl stop pve-cluster
systemctl stop corosync

pmxcfs -l

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

killall pmxcfs

systemctl start pve-cluster

Here’s an explanation for each step:

• systemctl stop pve-cluster: This command stops the pve-cluster service, which is responsible for managing the Proxmox VE cluster.

• systemctl stop corosync: This command stops the corosync service, which is used for cluster communication and coordination.

• pmxcfs -l: This command lists the current status of the pmxcfs service, which provides a distributed configuration file system for the cluster. If the pmxcfs service is properly stopped, the output of the pmxcfs -l command will be empty, indicating that there are no running pmxcfs processes on the node.

• rm /etc/pve/corosync.conf: This command removes the corosync.conf configuration file.

• rm -r /etc/corosync/*: This command removes all files and directories in the /etc/corosync directory, which is used for cluster configuration.

• killall pmxcfs: This command kills all running processes for the pmxcfs service.

• systemctl start pve-cluster: This command starts the pve-cluster service, which will initiate a new empty cluster connection on the current node.

Once you’ve removed the cluster connection, you can then start a new connection on the same node.