When a node starts up, how does it find the right cluster to join?

There is a line in the configuration file that looks like: 

# the multicast IP group in which we participate

group = 224.0.10.100 

The 'group' is a class D (multicast) IP address that determines to which cluster the node belongs. Different clusters can coexist on the same network if they have different group IP addresses.  We always recommend having different cluster names as well.

Unless there is a very good reason for it, multiple clusters should not exist on the same VLAN except perhaps in a test environment.  If you have any questions, please contact Tech Support