Setting up mod_jk in a cluster environment

[Garrick Dasbach]

I am presently working on setting up several tomcat clusters with in-memory session replication using Java groups.

My proposed setup would be:

2 Apache Servers running mod_jk
4 Tomcat servers broken into 2 clusters of 2.

To reduce network bandwidth, I only want to do in-memory session replication between the members of each cluster,
thus allowing 1 machine in each cluster to fail without the site crashing.

To acomplish this I need to be able to create 2 virtual clusters using mod_jk.

My thought was to create a load balanced worker, whose members are also load balanced workers.

Has anyone attempted this or know if it will work?

Any help would be appreciated.

Garrick Dasbach

Here's an example workers.properties file.

# Define 4 workers, 3 real workers using ajp12, ajp13, jni, the last one being a loadbalancing worker
worker.list=worker1, worker2, worker3, worker4, cluster1, cluster2, loadbalancer

# Set properties for worker1 (ajp13)
worker.worker1.type=ajp13
worker.worker1.host=server1
worker.worker1.port=8007
worker.worker1.lbfactor=100

# Set properties for worker2 (ajp13)
worker.worker2.type=ajp13
worker.worker2.host=server2
worker.worker2.port=8007
worker.worker2.lbfactor=100

# Set properties for worker3 (ajp13)
worker.worker2.type=ajp13
worker.worker2.host=server3
worker.worker2.port=8007
worker.worker2.lbfactor=100

# Set properties for worker4 (ajp13)
worker.worker2.type=ajp13
worker.worker2.host=server4
worker.worker2.port=8007
worker.worker2.lbfactor=100

# Set properties for lb1 (lb) which use worker1 and worker2
worker.cluster1.balanced_workers=worker1,worker2

# Set properties for lb1 (lb) which use worker3 and worker4
worker.cluster2.balanced_workers=worker3,worker4

# Set properties for lbprimary (lb) which use worker1 and worker2
worker.loadbalancer.balanced_workers=cluster1,cluster2