Product Clustering via the PPaaS Membership Scheme

The PPaaS membership scheme is a Carbon membership scheme. It is implemented to discover the Hazelcast cluster of a Carbon server via the topology.

How it works

Once a Carbon server starts it waits for the topology to initialize via the message broker. Next, it queries and gets the the member IP addresses of the given cluster, in the topology. Thereafter the Hazelcast network configuration is initialized for the queried IP addresses. As a result the above Hazelcast instance connects all the members in the cluster. Additionally, when a new member is added to the cluster all the other members are conceded to the new member.

Installation

Follow the steps given below to install the PPaaS Membership Scheme:

1. Apply the kernel patch0012 Carbon patch. The patch includes a modification in the Carbon Core component, allowing it to add third party membership schemes.

   For more information, see WSO2 patch application process.

2. Copy the following JAR files to the /dropins directory of the Carbon server:

   • activemq_client_5.10.0_1.0.0.jar
   • geronimo_j2ee_management_1.1_spec_1.0.1_1.0.0.jar
   • hawtbuf_1.9_1.0.0.jar
   • org.apache.commons.lang3_3.1.0.jar
   • org.apache.stratos.common-4.1.0.jar
   • org.apache.stratos.messaging-4.1.0.jar
   • private-paas-membership-scheme-4.1.0.jar

3. Update the <PPAAS_HOME>/repository/conf/axis2.xml file with the following configurations: 

   The cluster ID parameter needs to contain the cluster ID of the relevant carbon server cluster:

   <clustering class="org.wso2.carbon.core.clustering.hazelcast.HazelcastClusteringAgent" enable="true">
       <parameter name="membershipScheme">private-paas</parameter>
       <parameter name="membershipSchemeClassName">org.wso2.carbon.ppaas.PrivatePaaSBasedMembershipScheme</parameter>
       <parameter name="clusterIds">cluster-1,cluster-2</parameter> 
       <parameter name="localMemberPort">4000</parameter> 
   </clustering>

4. Update the JNDI configuration of the product to include the message broker configuration for the PPaaS Membership Scheme to connect to. Point the java.naming.provider to the AMQP port of the message broker.

   jndi.properties

   connectionfactoryName=TopicConnectionFactory
   java.naming.provider.url=tcp://localhost:61616
   java.naming.factory.initial=org.apache.activemq.jndi.ActiveMQInitialContextFactory