Sample 154: Load Balancing with Proxy Services
<definitions xmlns="http://ws.apache.org/ns/synapse">
<proxy name="LBProxy" transports="http" startOnLoad="true">
<target faultSequence="errorHandler">
<inSequence>
<send>
<endpoint>
<session type="simpleClientSession"/>
<loadbalance algorithm="org.apache.synapse.endpoints.algorithms.RoundRobin">
<endpoint>
<address uri="http://localhost:9001/services/LBService1">
<enableAddressing/>
<suspendDurationOnFailure>20</suspendDurationOnFailure>
</address>
</endpoint>
<endpoint>
<address uri="http://localhost:9002/services/LBService1">
<enableAddressing/>
<suspendDurationOnFailure>20</suspendDurationOnFailure>
</address>
</endpoint>
<endpoint>
<address uri="http://localhost:9003/services/LBService1">
<enableAddressing/>
<suspendDurationOnFailure>20</suspendDurationOnFailure>
</address>
</endpoint>
</loadbalance>
</endpoint>
</send>
<drop/>
</inSequence>
<outSequence>
<send/>
</outSequence>
</target>
<publishWSDL uri="file:repository/conf/sample/resources/proxy/sample_proxy_2.wsdl"/>
</proxy>
<sequence name="errorHandler">
<makefault response="true">
<code xmlns:tns="http://www.w3.org/2003/05/soap-envelope" value="tns:Receiver"/>
<reason value="COULDN'T SEND THE MESSAGE TO THE SERVER."/>
</makefault>
<send/>
</sequence>
</definitions>
Pre-requisites
- Deploy the LoadbalanceFailoverService in the sample Axis2 server (go to samples/axis2Server/src/LoadbalanceFailoverService and run 'ant')
-
Start 3 instances of the Axis2 server on different ports as follows
./axis2server.sh -http 9001 -https 9005 -name MyServer1
./axis2server.sh -http 9002 -https 9006 -name MyServer2
./axis2server.sh -http 9003 -https 9007 -name MyServer3 -
Start Synapse using the configuration numbered 154 (repository/conf/sample/synapse_sample_154.xml)
Unix/Linux: sh synapse.sh -sample 154
Windows: synapse.bat -sample 154
Executing the Client
This sample is similar to sample 54. The only notable difference is the use of a proxy service.
Execute the client as follows.
ant loadbalancefailover -Dmode=session -Dtrpurl=http://localhost:8280/services/LBProxy
You will get an output similar to the following.
[java] Request: 1 Session number: 1 Response from server: MyServer3
[java] Request: 2 Session number: 2 Response from server: MyServer2
[java] Request: 3 Session number: 0 Response from server: MyServer1
[java] Request: 4 Session number: 2 Response from server: MyServer2
[java] Request: 5 Session number: 1 Response from server: MyServer3
[java] Request: 6 Session number: 2 Response from server: MyServer2
[java] Request: 7 Session number: 2 Response from server: MyServer2
[java] Request: 8 Session number: 1 Response from server: MyServer3
[java] Request: 9 Session number: 0 Response from server: MyServer1
[java] Request: 10 Session number: 0 Response from server: MyServer1
...
You can see that session ID 0 is always directed to the server named MyServer1. That means session ID 0 is bound to MyServer1. Similarly session 1 and 2 are bound to MyServer3 and MyServer2 respectively.