Glassfish and mod_jk - Load Balancing and Session Replication - amazon-ec2

Question

I'm configuring an environment using Glassfish and mod_jk to provide load balancing and session replication.
My worker.properties is as follow:
worker.list=i1,i2,loadbalancer
# default properties for workers
worker.template.type=ajp13
worker.template.port=28080
worker.template.lbfactor=1
worker.template.socket_timeout=300
# properties for node1
worker.i1.reference=worker.template
worker.i1.host=10.0.0.93
#worker.worker1.host=node1
# properties for worker2
worker.i2.reference=worker.template
worker.i2.host=10.0.0.38
#worker.worker2.host=node2
# properties for loadbalancer
worker.loadbalancer.type=lb
worker.loadbalancer.balance_workers=i1,i2
worker.loadbalancer.sticky_session=true
The steps I've done are:
Created two nodes, n1 and n2 managed centrally (via SSH) from my server:
create-node-ssh --sshuser ubuntu --sshkeyfile /home/ubuntu/acme-auction.pem --nodehost 10.0.0.93 --installdir /home/ubuntu/glassfish3 n1
create-node-ssh --sshuser ubuntu --sshkeyfile /home/ubuntu/acme-auction.pem --nodehost 10.0.0.38 --installdir /home/ubuntu/glassfish3 n2
Created a cluster c1:
create-cluster --properties 'GMS_DISCOVERY_URI_LIST=generate:GMS_LISTENER_PORT=9090' c1
Created two instances:
create-instance --cluster c1 --node n1 i1
create-instance --cluster c1 --node n2 i2
start-instance i1
start-instance i2
Created an http-listener and a network-listener
create-http-listener --listenerport 28080 --listeneraddress 0.0.0.0 --defaultvs server jk-connector
create-network-listener --protocol http-listener-1 --listenerport 28080 --jkenabled true --target c1-config jk-connector
Then I created the routes JVM option:
create-jvm-options --target c1 "-DjvmRoute=\${AJP_INSTANCE_NAME}"
...and the sysyem properties according to jvmRoute:
create-system-properties --target i1 AJP_INSTANCE_NAME=i1
create-system-properties --target i2 AJP_INSTANCE_NAME=i2
I expected to be able to use my application visiting server_ip/app_name.
If I look at the cookies I can see:
a JSESSIONIDVERSION, format: value:number_of_operation
a JSESSIONID, format: value.i1
a JREPLICA, format: i2
(or the same with i2 and i1 exchanged).
This let me suppose the replication is set correctly, but when I stop i1, what I obtain is a blank page and no changes in cookies (I suppose JSESSIONID should change the last part, ".i1" in ".i2" to make the request be routed to i2, am I wrong?).
Thanks,
Andrea

Answer 1

Actually, it was a Serialization problem that made not possibile to serialize session and (as a consequence) switch to the other instance.
To make it serializable, just had to
make all object managed in the session implemet Serializable
for those who could not be serialized (eg EntityManager, Transactions...) add the "transient" modifier when declaring the property
Hope it helps,
Andrea