Proxmox Cluster Trouble Shooting

systemctl stop corosync.service 
systemctl stop pve-cluster.service
systemctl stop pvedaemon.service
systemctl stop pveproxy.service
 
systemctl start corosync.service 
systemctl start pve-cluster.service
systemctl start pvedaemon.service
systemctl start pveproxy.service

tcpdump -n -i eth1 multicast | grep 5404

journalctl | grep corosync

systemctl status corosync.service

pvecm expected 1

systemctl stop pve-cluster
pmxcfs -l 

• edit files, then run

killall mcxcfs
systemctl start pve-cluster

• corosync and Proxmox clustering need multicast traffic to be configured properly for cluster nodes to see each other.
• If a node keeps losing contact with other members make sure IGMP snooping is turned off at the switch and layer 2 level.
• If some nodes connect initially then disconnect after a few minutes take a look at the multicast configuration of the switches these nodes connect through.