Heartbeat is a daemon that provides cluster infrastructure (communication and membership) services to its clients. This allow clients to know appearance or disappearance of peer processes on other machines and to easily exchange message with them.(Heartbeat - Linux-HA)
Heartbeat clusters work only one on same network so if we setup different cluster (different authkeys) on same network it will show up as an error in log file. We can still setup more than one cluster in same network by setting different communication port for heartbeat.
The following example show configuration file for two different clusters in same network.
host configuration
192.168.123.1 host1.cluster1
192.168.123.2 host2.cluster1
192.168.123.3 host1.cluster2
192.168.123.4 host2.cluster2
first cluster
/etc/ha.d/ha.cf
debugfile /var/log/ha-debug
logfile /var/log/ha-log
logfacility local0
keepalive 2
deadtime 20
udpport 694
udp eth0
bcast eth0
node host1.cluster1 host2.cluster1
auto_failback on
debug 1
second cluster
/etc/ha.d/ha.cf
debugfile /var/log/ha-debug
logfile /var/log/ha-log
logfacility local0
keepalive 2
deadtime 20
udpport 695
udp eth0
bcast eth0
node host1.cluster2 host2.cluster2
auto_failback on
debug 1
Reference: http://www.gossamer-threads.com/lists/linuxha/users/57074
