[Linux-cluster] multicast howto

[Wolfgang Pauli]

Thanks!

First, I had to figure out how multicast works. Still don't fully understand 
it. I can ping 224.0.0.1 and I get responses from all hosts in the same 
subnet. It tried to ping 225.0.0.8 but that does not really work. But I don't 
know whether it has to.
I have changed the cluster.conf to have only two nodes. Just to get the basic 
understanding. I have node dream on subnet 210 and neo on 223. They still 
form their own clusters. Should I just try different addresses, or do the 
switches/routers have to be programmed for that?

regards,

wolfgang

<?xml version="1.0" ?>
<cluster config_version="2" name="alpha_cluster">
        <fence_daemon post_fail_delay="0" post_join_delay="3"/>
        <clusternodes>
                <clusternode name="dream" votes="1">
                        <multicast addr="225.0.0.9" interface="eth0"/>
                        <fence>
                                <method name="1">
                                        <device name="human" 
nodename="dream"/>
                                </method>
                        </fence>
                </clusternode>
                <clusternode name="neo" votes="1">
                        <multicast addr="225.0.0.9" interface="eth0"/>
                        <fence>
                                <method name="1">
                                        <device name="human" nodename="neo"/>
                                </method>
                        </fence>
                </clusternode>
        </clusternodes>
        <cman expected_votes="1" two_node="1">
                <multicast addr="225.0.0.9"/>
        </cman>
        <fencedevices>
                <fencedevice agent="fence_manual" name="human"/>
        </fencedevices>
        <rm>
                <failoverdomains/>
                <resources/>
        </rm>
</cluster>