Liferay 6.1 Clustering using mod_jk Connector

Clustering allows us to run portal instances on several parallel servers. The load is distributed across different servers, and even if any of the servers fails, the portal is still accessible via other cluster nodes. Clustering is crucial for scalable portal enterprise, as you can improve performance by simply adding more nodes to the cluster.

For larger installations, you would likely need a clustered configuration in order to handle the traffic of popular website. A cluster allows us to distribute the traffic coming in to website to several machines. Sure the cluster allows websites to handle more web traffic at a faster pace than it would be possible with a single machine.Definitely the portal works well in a clustered environment.

It is known fact that if we serve static resources like images, java script, css etc. through web server then we can improve response time. This fact also applies to Liferay portal as well. By default static resources of Portal, Portlet and Themes are served through Liferay portal server. Liferay portal adds certain overhead like servlet filters to serve these static resources. If we serve these static resources directly from web server then we can improve the response time. In majority of the production deployments web server is used in front of Liferay portal servers.

Use case: Setting up two Liferay tomcat instance which points to the same database along with Apache server on same windows machine

Pre-requisite:

· Install Apache 2.2 or latest stable version from here.

· Download Liferay 6.1 CE version from here.

· Install MySQL

Configuration Steps:

These configuration steps are based on the assumption that we have two Liferay instance running on different port using same MySQL database on windows machine.

Step 1: Copy static resources to apache web server

As a first step we need to copy static resources on Apache Web server document root directory.

· Copy all the directories or plugins except ROOT directory from Liferay_Home/tomcat/webapp/ to Apache webserver document root Apache 2.2/htdocs/.

· Copy html and layouttpl from Liferay_home/tomcat/webapps/ROOT/ to Apache 2.2/htdocs

Note: We copied whole directories just to make it simple. Ideally we should copy only static resource files like image, css and javascripts including their folder structure. For actual deployment a script can be written to do this task.

Step 2: Configure mod_jk

Mod_jk is the connector used to connect Tomcat JSP container with web servers. Configure it with Apache web server, you first of download it from here. Download the connector for correct version of Apache Web server depending upon the OS and Hardware configuration.

Step 3: Define mod_jk in Apache 2.2

Copy the mod_jk.so file from the downloaded connector to Apache2.2/modules/

Step 4: Create a properties file for defining cluster nodes

Create a workers.properties file under Apache2.2/conf/ with following properties

# Define list of workers that will be used

# for mapping requests

worker.list=tomcat1,tomcat2,loadbalancer,status

# Define Tomcat1

# modify the host as your host IP or DNS name.

worker.tomcat1.port=8010 // AJP Connector port of tomcat1

worker.tomcat1.host=localhost // host address of tomcat1

worker.tomcat1.type=ajp13 //AJP version type

worker.tomcat1.cachesize=10

worker.tomcat1.lbfactor=1

worker.tomcat1.socket_timeout=60

worker.tomcat1.connection_pool_timeout=60

worker.tomcat1.ping_mode=A

worker.tomcat1.ping_timeout=20000

worker.tomcat1.connect_timeout=20000

# Define Tomcat2

# modify the host as your host IP or DNS name.

worker.tomcat2.port=8011 // AJP connector port of tomcat2

worker.tomcat2.host=localhost // host address of tomcat2

worker.tomcat2.type=ajp13 // AJP version type

worker.tomcat1.cachesize=10

worker.tomcat2.lbfactor=1

worker.tomcat2.socket_timeout=60

worker.tomcat2.connection_pool_timeout=60

worker.tomcat2.ping_mode=A

worker.tomcat2.ping_timeout=20000

worker.tomcat2.connect_timeout=20000

# Load-balancing behaviour

worker.loadbalancer.type=lb

worker.loadbalancer.balance_workers=tomcat1,tomcat2 // define the tomcat node to manage load balancer

worker.loadbalancer.sticky_session=1 // type of sticky session

# Status worker for managing load balancer

worker.status.type=status

As shown in above code, mod_jk uses a file named workers.properties, defining where Apache looks for the Tomcat instances. worker.list is a comma-separated list of worker names. Each worker needs to define the port on which the connector is configured to work, e.g., 8010 for tomcat1 and 8011 for tomcat2.

Step 5: Create mod_jk configuration file in Apache 2.2 configuration directory

Create a new httpd-mod_jk.conf file under Apache 2.2/conf/extra with the following configuration properties

LoadModule jk_module modules/mod_jk.so //load mod_jk connector

JkWorkersFile conf/workers.properties //load workers.properties file that you created with your custom configuration

JkLogFile logs/mod_jk.log //define the log file path

JkLogStampFormat "[%a %b %d %H:%M:%S %Y]" //define the format

JkLogLevel info //Define the log level

JkShmFile logs/jk-runtime-status

JkMount /* loadbalancer

Jkunmount /*.jpg loadbalancer //load jpg files directory from Apache 2.2/htdocs for better performance

Jkunmount /*.gif loadbalancer //load gif files directory from Apache 2.2/htdocs for better performance

Jkunmount /*.png loadbalancer //load png files directory from Apache 2.2/htdocs for better performance

Jkunmount /*.ico loadbalancer //load ico files directory from Apache 2.2/htdocs for better performance

Jkunmount /*.js loadbalancer //load js files directory from Apache 2.2/htdocs for better performance

Jkunmount /*.css loadbalancer //load css files directory from Apache 2.2/htdocs for better performance

In this file we loaded mod_jk connector in apache web server and provided reference to worker.properties file. Which tells apache mod_jk connector to connect with Liferay tomcat server. We also provided log file configuration. Then we mapped all the requests to mod_jk connector by adding JkMount /* loadbalancer. Which means all the request received by apache web server will be delegated to any of the Liferay portal server. Then we unmount static resource requests from tomcat server by adding Jkunmount lines. So altogether this configuration tells that all requests except static resource requests should be served by tomcat and static resource requests should be served by apache web server from its document root. It can improve the response time at least 20-30%.

Step 6: Define Virtual host address to route to load balancer

Open httpd-vhosts.conf file under Apache 2.2/conf/extra/ directory and take a backup of whole contents to some another file and replace the whole content with following lines

NameVirtualHost *:80

NameVirtualHost *:81

JkMount /* loadbalancer

</VirtualHost>

JkMount /* loadbalancer

</VirtualHost>

Step 7: Modify httpd.conf file to do Clustering and load mod_jk in apache webserver.

Modify httpd.conf file under Apache 2.2/conf directory.

§ Normally Apache http server runs on port 80 or 8080, but if this port is busy sometimes as another windows processes runs on this server, so if you want to modify the port then search the keyword “Listen 8080” or “Listen 80” and replace it with “Listen 81”.

§ Uncomment the following lines

LoadModule proxy_module modules/mod_proxy.so

LoadModule proxy_ajp_module modules/mod_proxy_ajp.so

LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

LoadModule status_module modules/mod_status.so

Include conf/extra/httpd-vhosts.conf

§ Add the following lines at the end of the file

BalancerMember ajp://localhost:8010/ route=tomcat1 smax=15 max=50 loadfactor=20

BalancerMember ajp://localhost:8011/ route=tomcat2 smax=15 max=50 loadfactor=20

</Proxy>

ProxyPass balancer://mycluster/ stickysession=JSESSIONID

</Location>

SetHandler balancer-manager

Order Deny,Allow

Deny from all

Allow from localhost

</Location>

Include conf/extra/httpd-mod_jk.conf

Step 8: Configure Database

It’s assumed that you already have installed MySQL on your machine. Then go to your mysql command prompt and create a new database with the any name that you want.

create database liferay_loadbalancer;

Step 9: Configure portal-ext.properties file for both Liferay instances with following properties

# MySQL

jdbc.default.driverClassName=com.mysql.jdbc.Driver

jdbc.default.url=jdbc:mysql://localhost/liferay_loadbalancer?useUnicode=true&characterEncoding=UTF-8&useFastDateParsing=false

jdbc.default.username=root

jdbc.default.password=root

# EhCaching and clustering properties

net.sf.ehcache.configurationResourceName=/ehcache/hibernate-clustered.xml // ehCache configure file path for clustered environment

ehcache.multi.vm.config.location=/ehcache/liferay-multi-vm-clustered.xml // ehCache configure file path for multi VM environment

cluster.link.enabled=true // enable cluster link for indexing cluster and other features that depend on cluster link

lucene.replicate.write=true //setting to true if you want the portal to replicate an index write across all memebers of cluster. This is useful in some clustered environments where you wish each server instance to have its own copy of the Lucene search index. This is only relevant when using the default Lucene indexing engine.

Step 10: Configure server.xml file for first Liferay instances

§ Change the server port to 8006

§ Change the connector port to 8081 and redirectPort to 8444

<Connector port="8081" protocol="HTTP/1.1"

connectionTimeout="20000" redirectPort="8444" URIEncoding="UTF-8" />

§ Change the AJP connector port to 8010 and redirectPort to 8444. Make sure that URIEncoding must match to "UTF-8"

§ add jvmRoute="tomcat1" to following line

§ Replace the following line

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/> with this code

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"

channelSendOptions="6">

<Manager className="org.apache.catalina.ha.session.BackupManager"

expireSessionsOnShutdown="false"

notifyListenersOnReplication="true"

mapSendOptions="6"/>

<Membership className="org.apache.catalina.tribes.membership.McastService"

address="228.0.0.4" port="45564" frequency="500" dropTime="3000"/>

</Sender>

</Channel>

<Valve className="org.apache.catalina.ha.tcp.ReplicationValve"

filter=".*\.gif;.*\.js;.*\.jpg;.*\.png;.*\.htm;.*\.html;.*\.css;.*\.txt;"/>

</Cluster>

Step 11: Configure server.xml file for second Liferay instances

§ Change the server port to 8007

§ Change the connector port to 8082 and redirectPort to 8445

<Connector port="8082" protocol="HTTP/1.1"

connectionTimeout="20000" redirectPort="8445" URIEncoding="UTF-8" />

§ Change the AJP connector port to 8011 and redirectPort to 8444. Make sure that URIEncoding must match to "UTF-8"

§ add jvmRoute="tomcat2" to following line

§ Replace the following line

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/> with this code

<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"

channelSendOptions="6">

<Manager className="org.apache.catalina.ha.session.BackupManager"

expireSessionsOnShutdown="false"

notifyListenersOnReplication="true"

mapSendOptions="6"/>

<Membership className="org.apache.catalina.tribes.membership.McastService"

address="228.0.0.4" port="45564" frequency="500" dropTime="3000"/>

</Sender>

</Channel>

<Valve className="org.apache.catalina.ha.tcp.ReplicationValve"

filter=".*\.gif;.*\.js;.*\.jpg;.*\.png;.*\.htm;.*\.html;.*\.css;.*\.txt;"/>

</Cluster>

Step 12: Configure Context.xml file of both Liferay instances

In order to enable session replication, edit Liferay_Home/tomcat/conf/context.xml file and update <Context> with <Context distributable="true"/>. Do this configuration for both Liferay instances.

That’s done.

Now start apache, tomcat 1 and tomcat 2 server.

Once all servers started, go to browser and hit http://localhost:81/. It will load any one of the Liferay instance page (http://localhost:8081/) or (http://localhost:8082/).

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Tuesday, September 10, 2013

Liferay 6.1 Clustering using mod_jk Connector

Liferay 6.1 Clustering using mod_jk Connector

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