Re: Multi-server executions using tomcat and spring

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 13 Apr 2008 14:33:49 -0400

Message-ID:

<4802520a$0$90268$14726298@news.sunsite.dk>

bigmurali@gmail.com wrote:

I have a tomcat web app running on many servers in a farm all
connected by a switch that routes incoming requests to the servers by
picking a server in a round-robin fashion.

I have a servlet/jsp in my web application to trigger an action (say
re-reading a disk file). This triggering obviously can happen in only
one of the tomcat servers in the farm that the switch happened to pick
when I invoke my servlet from a browser/HTTP client.

So the question is, how can I make this update happen simultaneously
in all the instances of my webapp that are running on each one of the
servers in the farm?

Can Spring JMX help accomplish this if I expose the Spring bean that
performs this action as an MBean? or is the question simply absurd?

I'd be happy to hear any other suggestions to make this happen.

There must be many ways of achieving this.

I don't know Spring JMX, so I can not comment on that.

Two ways I can think of are:

1) store the loaded/reloaded data in a distributed cache
     like JBoss Cache (there are other), then the update
     will be propagated to all nodes

2) let the one node publish to a message queue that all nodes
     has a subscriber to and let the message trigger whatever
     needs to be done at all nodes

I am sure there are plenty of other solutions.

Arne