In this post we will see how to setup a load balanced JBoss or Tomcat environment with the fail-over capability.java
This post assumes that both Jboss/Tomcat and Apache httpd are setup and running properly.node
Configure Apache Httpd Step 1: Configure apache’s workers.propertiesGo to /usr/local/apache2/conf/extra and open workers.properties and configure the properties indicated in bold.web
# for mapping requests # The configuration directives are valid # for the mod_jk version 1.2.18 and later # worker.list=loadbalancer,status # Define node # modify the host as your host IP or DNS name. worker.node.port=8009 worker.node.host=192.168.0.3 #(IP or DNS name of the server on which Jboss is running) worker.node.type=ajp13 worker.node.lbfactor=1 worker.node2.port=8009 worker.node2.host=192.168.0.4 #(IP or DNS name of the server on which Jboss is running) worker.node2.type=ajp13 worker.node2.lbfactor=1 # Load-balancing behaviour worker.loadbalancer.type=lb worker.loadbalancer.balance_workers=node,node2 worker.loadbalancer.sticky_session=1 worker.status.type=status
The property balance_workers is used to specify the nodes to load balance. For example, if we specify only ‘node’, all requests will be routed to the server named ‘node’. Modify this to test that requests are going to both servers.express
Step 2: Configure mod-jk.confGo to /usr/local/apache2/conf/extra and open mod-jk.conf and configure the bold properties according to your requirements.apache
#Load mod_jk module # Specify the filename of the mod_jk lib LoadModule jk_module modules/mod_jk.so # Where to find workers.properties JkWorkersFile conf/extra/workers.properties # Where to put jk logs JkLogFile /var/apache/logs/mod_jk.log # Set the jk log level [debug/error/info] JkLogLevel debug # Select the log format JkLogStampFormat "[%a %b %d %H:%M:%S %Y]" # JkOptions indicates to send SSK KEY SIZE # Note: Changed from +ForwardURICompat. # See http://tomcat.apache.org/security-jk.html JkOptions +ForwardKeySize +ForwardURICompatUnparsed -ForwardDirectories JkOptions +FlushPackets # JkRequestLogFormat JkRequestLogFormat "%w %V %T" # Mount your applications JkMount /* loadbalancer # You can use external file for mount points. # It will be checked for updates each 60 seconds. # The format of the file is: /url=worker # /examples/*=loadbalancer JkMountFile conf/extra/uriworkermap.properties # Add shared memory. # This directive is present with 1.2.10 and # later versions of mod_jk, and is needed for # for load balancing to work properly # Note: Replaced JkShmFile logs/jk.shm due to SELinux issues. Refer to # https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=225452 JkShmFile /var/run/jk.shm # Add jkstatus for managing runtime data <Location /jkstatus/> JkMount status Order deny,allow Deny from all Allow from 127.0.0.1 </Location>
The JkMount /* loadbalancer indicates that all requests are to be routed through the load balancer.tomcat
Step 3: Go to /usr/local/apache2/conf and edit httpd.confAddsession
1.
Include conf/extra/mod-jk.conf
to the end of the file.app
Configure Tomcat/JBossThese settings need to be made for each of the nodes we intend on placing behind the load balancer.jvm
We need to modify the server.xml file which is located at
- For Tomcat
- ../apache-tomcat/conf/
- For JBoss
- ../jboss-5.1.0.GA/server/default/deploy/jbossweb.sar
Edit the following tag:
1.
&
lt
;Engine name=
"jboss.web"
defaultHost=
"localhost"
jvmRoute=
"node"
&
gt
;
where the jvmRoute attribute is configured to ‘node’ (which is the name we gave the first worker while configuring workers.properties.)
Next, locate the following tag and edit the port to be the same as while configuring the workers.properties.
1.
&
lt
;Connector protocol=
"AJP/1.3"
port=
"8009"
address=
"${jboss.bind.address}"
redirectPort=
"8443"
/&
gt
;
Configure the other node(s) accordingly.
Next, Start Apache httpd and the Jboss/tomcat node(s) that you have configured.