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Appendix B. Java Properties Reference

Read this appendix to learn about the JBoss HTTP Connector mod_cluster configuration properties that apply to a Tomcat server node.

B.1. Proxy Configuration

The configuration values are sent to proxies under the following conditions:
  • During server startup
  • When a proxy is detected through the advertise mechanism
  • During error recovery, when a proxy's configuration is reset.

Important

Clustering is not supported in Tomcat for JBoss Enterprise Web Server 2.0.

Table B.1. Proxy Configuration Values for Tomcat

ValueDefaultDescription
stickySessiontrueSpecifies whether subsequent requests for a given session should be routed to the same node, if possible.
stickySessionRemovefalseSpecifies whether the httpd proxy should remove session stickiness if the balancer is unable to route a request to the node to which it is stuck. This property is ignored if stickySession is false.
stickySessionFalsetrueSpecifies whether the httpd proxy should return an error if the balancer is unable to route a request to the node to which it is stuck. This property is ignored if stickySession is false.
workerTimeout-1Specifies the number of seconds to wait for a worker to become available to handle a request. When none of the workers of a balancer are unusable, mod_cluster retries after an interval (the interval value is the result of dividing the value of workerTimeout by 100) to find an usable worker. A value of -1 indicates that the httpd will not wait for a worker to be available and will return an error if no workers are available.
maxAttempts1Specifies the number of times the httpd proxy will attempt to send a given request to a worker before aborting. The minimum value is 1: try once before aborting.
flushPacketsfalseSpecifies whether packet flushing is enabled or disabled.
flushWait-1Specifies the time to wait before flushing packets. A value of -1 means wait forever.
ping10Time to wait (in seconds) for a pong answer to a ping.
smax-Specifies the soft maximum idle connection count. The maximum value is determined by the httpd thread configuration (ThreadsPerChild or 1).
ttl60Specifies the time (in seconds) idle connections persist, above the smax threshold.
nodeTimeout-1Specifies the time (in seconds) mod_cluster waits for the back-end server response before returning an error. mod_cluster always uses a cping/cpong before forwarding a request. The connectiontimeout value used by mod_cluster is the ping value.
balancermyclusterSpecifies the name of the load-balancer.
loadBalancingGroup-Optional parameter, which specifies how load is balanced across jvmRoutes within the same load balancing group. loadBalancingGroup is used in conjunction with partitioned session replication (for example, buddy replication).

Table B.2. Proxy Configuration Values for JBoss Enterprise Application Platform 6

AttributePropertyDefaultDescription
sticky-sessionstickySessiontrueSpecifies whether subsequent requests for a given session should be routed to the same node, if possible.
sticky-session-removestickySessionRemovefalseSpecifies whether the httpd proxy should remove session stickiness if the balancer is unable to route a request to the node to which it is stuck. This property is ignored if stickySession is false.
sticky-session-forcestickySessionForcetrueSpecifies whether the httpd proxy should return an error if the balancer is unable to route a request to the node to which it is stuck. This property is ignored if stickySession is false.
node-timeoutworkerTimeout-1Specifies the number of seconds to wait for a worker to become available to handle a request. When all the workers of a balancer are usable, mod_cluster will retry after a while (workerTimeout/100) to find an usable worker. A value of -1 indicates that the httpd will not wait for a worker to be available and will return an error if no workers are available.
max-attemptsmaxAttempts1Specifies the number of times the httpd proxy will attempt to send a given request to a worker before aborting. The minimum value is 1: try once before aborting.
flush-packetsflushPacketsfalseSpecifies whether packet flushing is enabled or disabled.
flush-waitflushWait-1Specifies the time to wait before flushing packets. A value of -1 means wait forever.
pingping10Time to wait (in seconds) for a pong answer to a ping.
smaxsmax-1Specifies the soft maximum idle connection count. The maximum value is determined by the httpd thread configuration (ThreadsPerChild or 1).
ttlttl-1Specifies the time (in seconds) idle connections persist, above the smax threshold.
load-balancing-grouploadBalancingGroup-Optional parameter, which specifies how load is balanced across jvmRoutes within the same load balancing group. loadBalancingGroup is used in conjunction with partitioned session replication (for example, buddy replication).