[Linux-HA] Re: Monitoring a monitored application

[Stephen Souness]

Slawomir Mroczek wrote:
> On Mon, 04 Dec 2006 15:26:38 +1300
> Stephen Souness <sounie at hotmail.com> wrote:
> 
>> At the moment I am considering having Tomcat start up before
>> heartbeat, and just having the web application (controlled from an
> 
> I'm afraid that hearbeat while starup will try to kill active tomcat
> resource and bring it up online again. Someone correct me if was wrong,
> but I think that's how hearbeat works. I think you should test it, just
> to be sure.

I was meaning that the web application (not Tomcat itself, but the 
servlets etc. that I have written) would be managed by heartbeat.  - So 
the start action might deploy the application and call something to 
ensure that it was successful, and the stop action might undeploy the 
application.

> 
>> OCF script) as the only resource.  However, in the event of a failure
>> on the active node I will still need some way of making the transfer
>> of the resource between nodes to be detectable by the load balancers.
> 
> As far as I know Tomcat with i.e. session replication enabled will
> handle failure of tomcat at any node. That's how this cluster works, and
> to say more load balancer should detect node failure and redirect
> connection to active node. However, in this case active-active tomcat
> configuration is required. Look at this:
> 

<-- Snip -->

So far we had been relying on a session replication by having sessions 
managed through a single JDBC driver which writes to both databases.

I might just have to get a little creative about how hearbeat starts / 
recovers / stops / monitors the web application.


--
Stephen