JBoss.orgCommunity Documentation

Chapter 14. Migration from mod_proxy

14.1. Workers
14.2. Balancers

As mod_cluster is a sophisticated balancer migration from mod_proxy to mod_cluster is strait forward. mod_cluster replaces a reverse proxy with loadbalancing. A reversed proxy is configured like:

ProxyRequests Off
<Proxy *>
Order deny,allow
Allow from all
</Proxy>
ProxyPass /foo http://foo.example.com/bar
ProxyPassReverse /foo http://foo.example.com/bar

All the general proxy parameters could be used in mod_cluster they work like in mod_proxy, only the balancers and the workers definitions are slightly different.

Mod_proxy Parameter

ClusterListener parameter

Remarks

min

-

Not supported in this version

max

-

mod_cluster uses mod_proxy default value

smax

smax

Same as mod_proxy

ttl

ttl

Same as mod_proxy

acquire

workerTimeout

Same as mod_proxy acquire but in seconds

disablereuse

-

mod_cluster will disable the node in case of error and the ClusterListener will for the reuse via the STATUS message

flushPackets

flushPackets

Same as mod_proxy

flushwait

flushwait

Same as mod_proxy

keepalive

-

Always on: OS KEEP_ALIVE is always used. Use connectionTimeout in the <Connector> if needed

lbset

-

Not supported

ping

ping

Same as mod_proxy Default value 10 seconds

lbfactor

-

The load factor is received by mod_cluster from a calculated value in the ClusterListener

redirect

-

Not supported lbfactor sent to 0 makes a standby node

retry

-

ClusterListener will test when the node is back online

route

JVMRoute

In fact JBossWEB via the JVMRoute in the Engine will add it

status

-

mod_cluster has a finer status handling: by context via the ENABLE/STOP/DISABLE/REMOVE application messages. hot-standby is done by lbfactor = 0 and Error by lbfactor = 1 both values are sent in STATUS message by the ClusterListener

timeout

nodeTimeout

Default wait for ever (http://httpd.apache.org/docs/2.2/mod/mod_proxy.html is wrong there)

ttl

ttl

Default 60 seconds

Mod_proxy Parameter

ClusterListener parameter

Remarks

lbmethod

-

There is only one load balancing method in mod_cluster "cluster_byrequests"

maxattempts

maxAttempts

Default 1

nofailover

stickySessionForce

Same as in mod_proxy

stickysession

StickySessionCookie/StickySessionPath

The 2 parameters in the ClusterListener are combined in one that behaves like in mod_proxy

timeout

workerTimeout

Default 1 seconds