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| |
| <document> |
| <properties> |
| <title>Apache Synapse - Sample 55</title> |
| </properties> |
| <body> |
| <section name="Sample 55: Session Affinity Load Balancing Between Fail-over Endpoints"> |
| <div class="xmlConf"><definitions xmlns="http://ws.apache.org/ns/synapse"> |
| |
| <sequence name="main" onError="errorHandler"> |
| <in> |
| <send> |
| <endpoint> |
| <!-- specify the session as the simple client session provided by Synapse for |
| testing purpose --> |
| <session type="simpleClientSession"/> |
| |
| <loadbalance> |
| <endpoint> |
| <failover> |
| <endpoint> |
| <address uri="http://localhost:9001/services/LBService1"> |
| <enableAddressing/> |
| </address> |
| </endpoint> |
| <endpoint> |
| <address uri="http://localhost:9002/services/LBService1"> |
| <enableAddressing/> |
| </address> |
| </endpoint> |
| </failover> |
| </endpoint> |
| <endpoint> |
| <failover> |
| <endpoint> |
| <address uri="http://localhost:9003/services/LBService1"> |
| <enableAddressing/> |
| </address> |
| </endpoint> |
| <endpoint> |
| <address uri="http://localhost:9004/services/LBService1"> |
| <enableAddressing/> |
| </address> |
| </endpoint> |
| </failover> |
| </endpoint> |
| </loadbalance> |
| </endpoint> |
| </send> |
| <drop/> |
| </in> |
| |
| <out> |
| <!-- Send the messages where they have been sent (i.e. implicit To EPR) --> |
| <send/> |
| </out> |
| </sequence> |
| |
| <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></div> |
| <subsection name="Objective"> |
| <p> |
| Demonstrate session aware load balancing in conjunction with fail-over |
| routing. |
| </p> |
| </subsection> |
| <subsection name="Pre-requisites"> |
| <p> |
| <ul> |
| <li> |
| Deploy the LoadbalanceFailoverService in the sample Axis2 server (go to |
| samples/axis2Server/src/LoadbalanceFailoverService and run 'ant') |
| </li> |
| <li> |
| Start 4 instances of the Axis2 server on different ports as follows |
| <div class="command">./axis2server.sh -http 9001 -https 9005 -name MyServer1<br/> |
| ./axis2server.sh -http 9002 -https 9006 -name MyServer2<br/> |
| ./axis2server.sh -http 9003 -https 9007 -name MyServer3<br/> |
| ./axis2server.sh -http 9004 -https 9008 -name MyServer4</div> |
| </li> |
| <li> |
| Start Synapse using the configuration numbered 55 (repository/conf/sample/synapse_sample_55.xml) |
| <div class="command"> |
| Unix/Linux: sh synapse.sh -sample 55<br/> |
| Windows: synapse.bat -sample 55 |
| </div> |
| </li> |
| </ul> |
| </p> |
| </subsection> |
| <subsection name="Executing the Client"> |
| <p> |
| This configuration also uses 'simpleClientSession' to bind session ID values to |
| servers as in <a href="sample54.html">sample 54</a>. But fail-over endpoints are |
| specified as the child endpoints of the load balance endpoint. Therefore sessions |
| are bound to the fail-over endpoints. Session information has to be replicated |
| among the servers listed under each failover endpoint using some clustering |
| mechanism. Therefore, if one endpoint bound to a session failed, successive requets |
| for that session will be directed to the next endpoint in that failover group. |
| Run the client using the following command to observe this behaviour. |
| </p> |
| <div class="command">ant loadbalancefailover -Dmode=session</div> |
| <p> |
| You can see a client output as shown below. |
| </p> |
| <div class="consoleOutput">... |
| [java] Request: 222 Session number: 0 Response from server: MyServer1 |
| [java] Request: 223 Session number: 0 Response from server: MyServer1 |
| [java] Request: 224 Session number: 1 Response from server: MyServer1 |
| [java] Request: 225 Session number: 2 Response from server: MyServer3 |
| [java] Request: 226 Session number: 0 Response from server: MyServer1 |
| [java] Request: 227 Session number: 1 Response from server: MyServer1 |
| [java] Request: 228 Session number: 2 Response from server: MyServer3 |
| [java] Request: 229 Session number: 1 Response from server: MyServer1 |
| [java] Request: 230 Session number: 1 Response from server: MyServer1 |
| [java] Request: 231 Session number: 2 Response from server: MyServer3 |
| ...</div> |
| <p> |
| Note that session 0 is always directed to MyServer1 and session 2 is directed to |
| MyServer3. No requests are directed to MyServer2 and MyServer4 as they are kept |
| as backups by fail-over endpoints. Now shutdown the server named MyServer1 while |
| running the sample. You will observe that all successive requests for session 0 |
| is now directed to MyServer2, which is the backup server for MyServer1's group. |
| This is shown below, where MyServer1 was shutdown after the request 534. |
| </p> |
| <div class="consoleOutput">... |
| [java] Request: 529 Session number: 2 Response from server: MyServer3 |
| [java] Request: 530 Session number: 1 Response from server: MyServer1 |
| [java] Request: 531 Session number: 0 Response from server: MyServer1 |
| [java] Request: 532 Session number: 1 Response from server: MyServer1 |
| [java] Request: 533 Session number: 1 Response from server: MyServer1 |
| [java] Request: 534 Session number: 1 Response from server: MyServer1 |
| [java] Request: 535 Session number: 0 Response from server: MyServer2 |
| [java] Request: 536 Session number: 0 Response from server: MyServer2 |
| [java] Request: 537 Session number: 0 Response from server: MyServer2 |
| [java] Request: 538 Session number: 2 Response from server: MyServer3 |
| [java] Request: 539 Session number: 0 Response from server: MyServer2 |
| ...</div> |
| </subsection> |
| </section> |
| <p><a href="../samples.html">Back to Catalog</a></p> |
| </body> |
| </document> |
