Using multiple node support and load balancing policy in Kundera

Multiple node support and configuring load balancing policies are now supported within Kundera(Cassandra only). Please refer here for more details.Multiple node support can be used as:

Multiple nodes on same port

In case all Cassandra nodes are running on same port(say 9160). So minimal required configuration is:

<property name="kundera.nodes" value="192.168.120.134,192.168.120.111,192.168.120.121,192.168.120.141" />
<property name="kundera.port" value="9160" />

in persistence.xml.

To configure load balancer for available set of properties(see Load balancing specific properties section), you need to create an external file say(KunderaNodeConfig.xml) as:

<?xml version="1.0" encoding="UTF-8"?>
<clientProperties>
  <datastores>
   <dataStore>
	<name>cassandra</name>
	<connection>
  	 <servers>
        </servers>
     <!-- Load balancing specific configuration -->
    <properties>
	<property name="loadbalancing.policy" value="roundrobin"></property>
        <property name="retry" value="true"></property>
        <property name="retry.delay" value="1"></property>
        <property name="max.wait" value="3000"></property> 
    </properties>
 </connection>
</dataStore>
</datastores>
</clientProperties>

Multiple nodes with different port

In case different Cassandra nodes are running on different ports, it is required to map such configurations in form of "external file" configuration as(say KunderaNodeConfig.xml):

<?xml version="1.0" encoding="UTF-8"?>
<clientProperties>
  <datastores>
   <dataStore>
	<name>cassandra</name>
	<connection>
  	 <servers>
	  <server>
	   <host>192.168.120.134</host>
	   <port>9160</port>
	   <properties>
	    <property name="testonborrow" value="true"></property>
	    <property name="testwhileidle" value="true"></property>
    	    <property name="testonconnect" value="true"></property>
	    <property name="testonreturn" value="true"></property>
	    <property name="socket.timeout" value="120000"></property>
	    <property name="failover.policy" value="on.fail.try.one.next.available"></property>
	    <property name="retry" value="true"></property>
	    <property name="kundera.pool.size.max.active" value="31"></property>
 	 </properties>
	</server>

	<server>
	  <host>192.168.120.111</host>
	  <port>9161</port>
  	  <properties>
	     <property name="testonborrow" value="true"></property>
	     <property name="testwhileidle" value="true"></property>
	     <property name="testonconnect" value="true"></property>
	     <property name="testonreturn" value="true"></property>
	     <property name="socket.timeout" value="120000"></property>
	     <property name="failover.policy" value="on.fail.try.one.next.available"></property>
	     <property name="retry" value="true"></property>
	     <property name="kundera.pool.size.max.active" value="33"></property>
	 </properties>
       </server>
    </servers>
     <!-- Load balancing specific configuration -->
    <properties>
	<property name="loadbalancing.policy" value="roundrobin"></property>
        <property name="retry" value="true"></property>
        <property name="retry.delay" value="1"></property>
        <property name="max.wait" value="3000"></property> 
    </properties>
 </connection>
</dataStore>
</datastores>
</clientProperties>

Next step is to map such external configuration file(KunderaLoadConfig.xml) within persistence.xml as:

<property name="kundera.client.property" value="KunderaLoadConfig.xml" /> 

Managing Load balancing policy

Load balancing specific configuration can be defined within external configuration file as:

 <properties>
	<property name="loadbalancing.policy" value="roundrobin"></property>
        <property name="retry.delay" value="1"></property>
    </properties>

Load balancing specific properties

Available set of properties for load balancing are:

Property	Value
failover.policy	on.fail.try.all.available,on.fail.try.one.next.available,fail.fast
retry	true/false
loadbalancing.policy	roundrobin,leastactive
testonborrow	true/false
testonreturn	true/false
testonconnect	true/false
testwhileidle	true/false
socket.timeout	Socket time out(in seconds)
kundera.pool.size.max.active	Maximum active number of connection in pool.
retry.delay	retry delay(in seconds)
max.wait	wait time in case all active connections are busy(in mili seconds)