Coherence

Specifying a Cluster's Name

• A cluster name is a user-defined name that uniquely identifies a cluster from other clusters that run on the network.
• Cluster members must specify the same cluster name to join and cluster.
• A cluster member does not start if the wrong name is specified when attempting to join an existing     cluster.
• A unique cluster name is often used with a unique multicast port to create distinct clusters on the same network.  

To specify a cluster name

<?xml version='1.0'?>

<coherence xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns="http://xmlns.oracle.com/coherence/coherence-operational-config"
   xsi:schemaLocation="http://xmlns.oracle.com/coherence/
   coherence-operational-config coherence-operational-config.xsd">
   <cluster-config>
      <member-identity>
         <cluster-name system-property="tangosol.coherence.cluster">MyCluster
         </cluster-name>
      </member-identity>
   </cluster-config>
</coherence>

The tangosol.coherence.cluster system property is used to specify the cluster name instead of using the operational override file. For example:

-Dtangosol.coherence.cluster=name

You can set this in your run.sh file as JAVA_OPTS.

Configuring Multicast Communication

Multicast communication is configured in an operational override file(tangosol-coherence-override.xml) within the <multicast-listener> node.

Specifying a Cluster's Multicast Address

• A multicast address (IP address and port) can be specified for a cluster member
• Cluster members must use the same multicast address and port to join and cluster
• Distinct clusters on the same network must use different multicast addresses.

To specify a cluster multicast address, edit the operational override file and add both an <address> and <port> element and specify the address and port to be used by the cluster member. For example:

<?xml version='1.0'?>

<coherence xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns="http://xmlns.oracle.com/coherence/coherence-operational-config"
   xsi:schemaLocation="http://xmlns.oracle.com/coherence/
   coherence-operational-config coherence-operational-config.xsd">
   <cluster-config>
      <multicast-listener>
         <address system-property="tangosol.coherence.clusteraddress">224.3.6.0
         </address>
         <port system-property="tangosol.coherence.clusterport">3059</port>
      </multicast-listener>
   </cluster-config>
</coherence>

The tangosol.coherence.clusteraddress and tangosol.coherence.clusterport system properties are used to specify the cluster multicast address instead of using the operational override file. 

For example:

-Dtangosol.coherence.clusteraddress=224.3.6.0 -Dtangosol.coherence.clusterport=3059