The node directive tells what machines are in the cluster. The syntax of the node directive is simple:
node nodename1 nodename2 ...
Node names in the directive must (normally) match the "uname -n" of that machine.
You can declare multiple node names in one directive. You can also use the directive multiple times. Normally every node in the cluster must be listed in the ha.cf file, including the current node, unless the autojoin directive is enabled.
Note that starting with 2.0.4, the node directive is not completely authoritative with regard to nodes heartbeat will communicate with. If a node has ever been added in the past, it will tend to remain in the hostcache file more until it's manually removed. See Also: http://www.osdl.org/developer_bugzilla/show_bug.cgi?id=1226