force remove a node from proxmox node tree

If you like me did not follow the rule of shuting down a server before removing the node from proxmox cluster, you will get a broken node in your node tree, to force remove it just do the following

# rm -rf /etc/pve/nodes/HOSTNAME

From

http://undefinederror.org/how-to-reset-cluster-configuration-in-proxmox-2/