All / Most elections going to one node
jmsjr Jun 18, 2013 9:24 PMmod_cluster-1.2.3
Apache httpd 2.2.24
JBoss AS Final 7.1.3 also modules for mod_cluster upgrade from 1.2.1 to 1.2.3
All of the above built from source
httpd+mod_cluster as load balancer for 2 JBoss nodes running 7.1.3. Final
Failover is working fine, that's not an issue.
What I am seeing is that the node election is mostly, if not all, going to one node.
There are at least 5 users testing the system most of the time.
Sessions are not long-lived, mostly short-lived ( Using @ViewScoped JSF managed beans ).
Users would open up and close different "views" during the day.
Here's the output from httpd mod_cluster_manager page:
mod_cluster/1.2.3.Final
Auto Refresh show DUMP output show INFO output
Node 549de3eb-7aa1-3456-bcc1-8c884bd3bfe0 (ajp://172.21.5.217:8009):
Enable Contexts Disable Contexts
Balancer: bpm-webcluster,LBGroup: ,Flushpackets: Off,Flushwait: 10000,Ping: 10000000,Smax: 26,Ttl: 60000000,Status: OK,Elected: 2545,Read: 21757179,Transferred: 5317754,Connected: 0,Load: 80
Virtual Host 1:
Contexts:
/insurance, Status: ENABLED Request: 0 Disable
Aliases:
default-host
xxxx1.yyyy.zzzz
xxxx2.yyyy.zzzz
Node a80cee80-e1d4-3d88-8cd8-64413f9732eb (ajp://172.21.5.218:8009):
Enable Contexts Disable Contexts
Balancer: bpm-webcluster,LBGroup: ,Flushpackets: Off,Flushwait: 10000,Ping: 10000000,Smax: 26,Ttl: 60000000,Status: OK,Elected: 0,Read: 0,Transferred: 0,Connected: 0,Load: 79
Virtual Host 1:
Contexts:
/insurance, Status: ENABLED Request: 0 Disable
Aliases:
default-host
xxxx1.yyyy.zzzz
xxxx2.yyyy.zzzz
Both JBoss nodes running in standalone-ha.xml configuration, with the following load providers:
<subsystem xmlns="urn:jboss:domain:modcluster:1.1">
<mod-cluster-config advertise-socket="modcluster" connector="ajp">
<dynamic-load-provider history="5">
<load-metric type="busyness" weight="3"/>
<load-metric type="heap" weight="2"/>
<load-metric type="mem" weight="1"/>
</dynamic-load-provider>
</mod-cluster-config>
</subsystem>
Both nodes have identical hardware ( VMWare templates ) and running processes.
I was thinking:
1) If both JBoss nodes return the same load factor, does httpd+mod_cluster always elect the first node on its list ?
2) Is there a way to add some randomness to the load factor, but only when all nodes return the same load factor ?