JBoss.orgCommunity Documentation
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 3 |
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 |