HTTP Session failover, A one shot deal, Jboss3.2.1 Tomcat &
After getting a simple Jboss cluster set up on 2 Solairs nodes, the HTTP session failover is not functioning properly. I set up JBoss 3.2.1 on a cluster of 2 Solaris boxes with an Apache 1.3.27 - jk2 load balancer. This in of itself took a few hours and I used the following thread for most of my setup questions http://www.jboss.org/modules/bb/index.html?module=bb&op=viewtopic&t=
My webapp has a simple jsp that does a httpSession.setAttribute("myHashSet", hashSet) on every invocation. hashSet contains a set of Strings, a new string added during each invocation of the jsp. Since I use stickySession=1 for the loadbalancer, the initial node fielding the request handles all subsequent requests unless that node becomes unavailable.
In my example the sticky session ensures all requests go to "node1". Then I pull "node1" out by simply shutting JBoss down. This works just fine, all data in the session is replicated to the new node "node2". Now, let me try this again, starting out with "node1" handling the requests, then force a failover to "node2" by simply taking "node1" out of the cluster (setting disabled=1 for node1 in workers2.props). With load now directed at "node2" the session data replicated from "node1" is available, good!. Finally, I add data through "node2", then force a failover again, this time to "node1" (disabling "node2" and enabling "node1", again using workers2.props). After the second failover the data is no longer replicated. In other words, the data that I entered on "node2" is not available after the second failover to "node1".
node1(enter A, B) --failover--> node2 (A, B still there, now enter C) --failover--> node1( only A, B available)
Sorry this is so complicated, describing behavior in clustered environments always is, I couldn't imagine trying to describe this using more than 2 nodes.
The conclusion I have come to is, JBoss HTTP session replication is a one shot deal. The data in a replicated session should be replicated to all nodes. In this case both nodes were running throughout the test, each was logging HttpSessionHA messages indicating that replication was taking place. But the replicated data seems to only be recoverable once after the first failover.
Could anyone provide some information about how to achieve multiple failovers?
Steve
===== SETUP INFO================================
My configuration consists of:
mod_jk2:
[lb:lb2]
debug=6
timeout=30
attempts=3
stickySession=1
[channel.socket:txsldevnode01:8009]
debug=6
tomcatId=node1
lb_factor=100
group=lb2
disabled=0
[channel.socket:txsldevnode02:8009]
debug=6
tomcatId=node2
lb_factor=100
group=lb2
disabled=0
# Uri mapping
[uri:/mytestweb/servlet/*]
group=lb2
[uri:/mytestweb/*.jsp]
group=lb2
using the "all" configuration set:
all/deploy/jbossweb-tomcat.sar/META-INF/jboss-service.xml
<Engine .... jvmRoute="node1"> & <Engine .... jvmRoute="node2">
instant
Both nodes have an entry in /etc/hosts for resolving each other, and I'm not using IP address in any configuration including Apache or jk2.
My webapp has a simple jsp that does a httpSession.setAttribute("myHashSet", hashSet) on every invocation. hashSet contains a set of Strings, a new string added during each invocation of the jsp. Since I use stickySession=1 for the loadbalancer, the initial node fielding the request handles all subsequent requests unless that node becomes unavailable.