Problem:
After removing a node from a Proxmox cluster, the node that remains active, the cluster is left in non-operational status: you can not create virtual machines, the machine deletion fails, you can not unblock the machines, the file systems /etc/ pve is in a read-only state and many more problems.
This is because in a cluster of 2 nodes, you have 2 votes defined (server) to access the quorum and since only one server is active one, the quorum enters a read-only state.
Errors: 1) Status: stopped: unexpected status 2) root@proxmox-aurlen-01~# qm unlock 140 unable to open file '/etc/pve/nodes/DH4-R1-20-RH2285-UP/qemu-server/140.conf.tmp.11240' - Permission denied 3) /etc/pve/nodes/proxmox-aurlen-01/qemu-server# chmod 775 102.conf chmod: changing permissions of ‘102.conf’: Function not implemented ... Stop disk image '/var/lib/vz/images/133/vm-133-disk-1.raw' does not exists trying to aquire cfs lock 'file-user_cfg' ...TASK ERROR: cluster not ready - no quorum?
Workaround:
For a two node cluster execute the command:
pvecm expected 1
After the execution of the command you can already do the usual operations like create delete unblock etc. etc.,
root@ proxmox-aurlen-01:/etc/pve/qemu-server# qm unlock 140 root@ proxmox-aurlen-01:/etc/pve/qemu-server#
Final solution
Activate the second node.
Reference:
https://pve.proxmox.com/wiki/Proxmox_VE_2.0_Cluster#Two_nodes_cluster_and_quorum_issues