Documentation Version: 3.5 - Publication Date : Jun 17, 2015

Creating Cluster Groups

You can create cluster groups. To do this, use the group configuration element.

By specifying a group name and group password, you can separate your clusters in a simple way. Example groupings can be by development, production, test, app, etc. The following is an example declarative configuration.

<hazelcast>
  <group>
    <name>app1</name>
    <password>app1-pass</password>
  </group>
  ...
</hazelcast>

You can also define the cluster groups using the programmatic configuration. A JVM can host multiple Hazelcast instances. Each Hazelcast instance can only participate in one group. Each Hazelcast instance only joins to its own group, it does not mess with other groups. The following code example creates three separate Hazelcast instances: h1 belongs to the app1 cluster, while h2 and h3 belong to the app2 cluster.

Config configApp1 = new Config();
configApp1.getGroupConfig().setName( "app1" ).setPassword( "app1-pass" );

Config configApp2 = new Config();
configApp2.getGroupConfig().setName( "app2" ).setPassword( "app2-pass" );

HazelcastInstance h1 = Hazelcast.newHazelcastInstance( configApp1 );
HazelcastInstance h2 = Hazelcast.newHazelcastInstance( configApp2 );
HazelcastInstance h3 = Hazelcast.newHazelcastInstance( configApp2 );