On node1 (with guests)
Create a new cluster or get join information.
On node2 (with guests)
scp -r /etc/pve/nodes/* to node1:/etc/pve/nodes (ex. scp -r /etc/pve/nodes/* to 192.168.x.x:/etc/pve/nodes )
rm -r /etc/pve/nodes/* Join cluster.
NOTE: The joining machine will sync its VM’s from the Clusters host, including its PCI mappings and Firewall rules. If you have any on the joining node, back these up before hand!