Re: Keepalived for IP failover only (no load balancing)

On Sun, Dec 08, 2013 at 07:55:09AM -0500, Aron West wrote:
> Hi everyone,
> 
> I have been testing Keepalived for the past couple of months on SLES 11sp2
> and haven't experienced any problems compiling or getting it running
> (including the latest release 1.29).  I have installed the SLES HA
> extensions, so the LVS patch has been applied to the Linux kernel.
> 
> I've been working on a two node active/passive setup with Keepalived health
> checks for monitoring Tomcat and Glassfish application servers. I have
> studied the options in the configuration file to answer the following
> question:  is there a simple way to disable load balancing and just rely on
> Keepalived for IP failover?  I would like my master node to stay the master
> until one of the monitored services (like Tomcat) fails in which case, the
> backup node takes over.  By default Keepalived uses round robin scheduling
> (rr), so even when no service has failed master and backup keep switching
> places.   I've searched extensively about this issue, experimented with
> nopreempt, setting different priorities, setting both nodes to backup
> etc.   I have found other posts on the Internet asking this question
> without any responses.
> 
> Thanks for any insights,
> 
> Aron

It is simple to use keepalived for IP failover only with no load
balancing. You simple defined your vrrp_instance and do not create any
virtual_servers. At least that is one way to do it. To monitor your
application and trigger IP failover, you will need to use a
vrrp_script. This is actually a common configuration for users who
want keepalived to handle IP failover but use haproxy for
load-balancing.

Your other alternative is to use something like Pacemaker. This is
probably better suited for what you are trying to accomplish.

Ryan


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