Hi, Some commercial load balancers achieve this by manipulating DNS servers with very low time-to-live (TTL) values (e.g. 60 seconds).
However problems occurs when clients don't obey or observe the TTL values specified by the DNS servers. This frequently occurs with browsers, Java and other client-side software that caches DNS entries well beyond the TTL time. Certain (older) versions of Java cached positive DNS results _indefinitely_ by default irrespective of TTL (yes, really). Also remember that some DNS servers used by ISPs may deliberately ignore TTL values < 1-5 minutes (variable, depends upon ISP). I'm not saying it won't work... just to be aware of these issues, which have bit me in the past. To answer your question, I don't know of a resource agent that does this, however it would be possible to write one - it just depends upon your DNS server. Power-DNS can probably be made to do this with its backend in LDAP. Don't know how easy it would be to control BIND to do this though. Regards, Brett On 30 November 2010 11:21, Michael Kromer <[email protected]>wrote: > Hi, > > wanted to know if anyone has an idea to manipulate DNS-entries in case > of failover, by example having 3 nodes communicating with ips from > different locations (which kills IPAddr(2) for takeover) and having them > delivering ressources by same DNS-entry. Idea would be to remove an IP > as soon as ressources on that node are not available anymore, and adding > itself back as soon as everything is running. > > Any ideas? > > - mike > _______________________________________________ > Linux-HA mailing list > [email protected] > http://lists.linux-ha.org/mailman/listinfo/linux-ha > See also: http://linux-ha.org/ReportingProblems > -- Best Regards, Brett Delle Grazie _______________________________________________ Linux-HA mailing list [email protected] http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
