4.4.3. Replacing a Corosync Node
The five-step guide to replacing an existing cluster node:
Make sure the old node is completely stopped
Give the new machine the same hostname and IP address as the old one
Install the cluster software :-)
Copy /etc/corosync/corosync.conf and /etc/corosync/authkey (if it exists) to the new node
Start the new cluster node
If a log message containing "Invalid digest" appears from Corosync, the keys are not consistent between the machines.