On Oct 23, 2010, at 4:12 PM, Robinson, Eric wrote: >>> "3-node cluster" is much easier to say than to configure, >>> apparently. :-) > >> It really isn't :) > > Encouraged by your "it really isn't," I now press forward. :-) > > Based on what I'm hearing, this is what I think I have learned... > > It is possible to build a 3-node cluster with redundant heartbeat paths, > but I need to use two switches, something like this: > > > -------------SWITCHED NET #1------(192.168.10.0/24)----------------- > | | | > | | | > |-----------------| |-----------------| |---------------------| > | | | | | | | | | > | |--bond0--| | | |--bond0--| | | |--bond0--| | > | eth0 eth1 | | eth0 eth1 | | eth0 eth1 | > | | | | | | > | SERVER_A | | SERVER_B | | SERVER_C | > | | | | | | > | eth2 | | eth2 | | eth2 | > | | | | | | | | | > |-----------------| |-----------------| |---------------------| > | | | > | | | > -------------SWITCHED NET #2-------(192.168.20.0/24)----------------- > > > That way, if something happens to switched network #1, Corosync can > still track node status through switched net #2. > > Once this configuration is built, I can use Pacemaker with resource > constraints to ensure that resource R1 can only run on SERVER_A or > SERVER_C (usually A) and resource R2 can only run on SERVER_B and > SERVER_C (usually C) and SERVER_C acts as a failover for both resources. > > Is this correct? >
That's correct. And since it's a 3 node cluster you can make this using simple constraints like this: location R1-prefers-A R1 100: SERVER_A location R1-not-B -inf: SERVER_B location R2-prefers-B R2 100: SERVER_B location R2-not-A -inf: SERVER_A Vadym _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
