Hi, On 17 February 2011 12:58, Carlos G Mendioroz <[email protected]> wrote: > Hi, > I've found that ipaddr2 can use clusterip when running as clone. > (please correct me if I use some word in a not correct way, > denoting I fail to get some concept) > > But my understanding is that clusterip might be beneficial also > in the active/standby case because of its use of a single mac > address.
Not really - its simpler (networking wise) and safer to use floating IP addresses for standard HA. Otherwise all traffic is being duplicated to both nodes which ties up bandwidth unnecessarily - that's the major downside to ClusterIP. Indeed it could be argued that with multiple floating IPs used with DNS round-robin, ClusterIP becomes almost unnecessary. FYI ClusterIP target in iptables has been deprecated, the successor is cluster-match but I don't think there is a resource agent which uses it yet. > > I would create the active with 1 node and the standby alike, > but "demote" the standby by forcing it not to answer. Why? - you lose functionality here such as the system _automatically_ correcting for failure - which is, I assume, why you want to use Pacemaker. > > Questions: > -any obvious issue here ? > -I see some posts with CLUSTERIP and ARP related issues, > but I fail to understand a case where this happens. > If someone has a failure case I would appreciate it. Our failure cases: (1) It didn't work at all - resolved by (a) (2) It didn't work under failure conditions (pulling the network cable and/or power on one node) - we got lost connections, no response etc. resolved by (b) Our solutions were: (a) Enable multicast mac addresses on the switch/firewall (otherwise it doesn't work at all) and (b) adding a static ARP entry for the IP to cluster mac address in the switch/firewall. -- Best Regards, Brett Delle Grazie _______________________________________________ Pacemaker mailing list: [email protected] http://oss.clusterlabs.org/mailman/listinfo/pacemaker Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker
