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| |
| <document> |
| <properties> |
| <title>Apache Synapse - Sample 53</title> |
| </properties> |
| <body> |
| <section name="Sample 53: Fail-over Routing Among 3 Endpoints"> |
| <div class="xmlConf"><definitions xmlns="http://ws.apache.org/ns/synapse"> |
| |
| <sequence name="main" onError="errorHandler"> |
| <in> |
| <send> |
| <endpoint> |
| <failover> |
| <endpoint> |
| <address uri="http://localhost:9001/services/LBService1"> |
| <enableAddressing/> |
| <suspendDurationOnFailure>60</suspendDurationOnFailure> |
| </address> |
| </endpoint> |
| <endpoint> |
| <address uri="http://localhost:9002/services/LBService1"> |
| <enableAddressing/> |
| <suspendDurationOnFailure>60</suspendDurationOnFailure> |
| </address> |
| </endpoint> |
| <endpoint> |
| <address uri="http://localhost:9003/services/LBService1"> |
| <enableAddressing/> |
| <suspendDurationOnFailure>60</suspendDurationOnFailure> |
| </address> |
| </endpoint> |
| </failover> |
| </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 the fail-over routing capabilities of Synapse. In fail-over routing |
| messages are sent to a designated primary endpoint. When the primary endpoint |
| fails, Synapse fails over to the one of the backup endpoints. |
| </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 3 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</div> |
| </li> |
| <li> |
| Start Synapse using the configuration numbered 53 (repository/conf/sample/synapse_sample_53.xml) |
| <div class="command"> |
| Unix/Linux: sh synapse.sh -sample 53<br/> |
| Windows: synapse.bat -sample 53 |
| </div> |
| </li> |
| </ul> |
| </p> |
| </subsection> |
| <subsection name="Executing the Client"> |
| <p> |
| Above configuration sends messages with the fail-over behavior. Initially the |
| server at port 9001 is treated as primary and other two are treated as backups. |
| Messages are always directed only to the primary server. If the primary server |
| fails, next listed server is selected as the primary. Thus, messages are sent |
| successfully as long as there is at least one active server. To test this, run |
| the loadbalancefailover client to send infinite requests as follows: |
| </p> |
| <div class="command">ant loadbalancefailover</div> |
| <p> |
| You can see that all requests are processed by MyServer1. Now shutdown MyServer1 |
| and inspect the console output of the client. You will observe that all subsequent |
| requests are processed by MyServer2. (MyServer 1 was shutdown after request 127) |
| </p> |
| <div class="consoleOutput">... |
| [java] Request: 125 ==> Response from server: MyServer1 |
| [java] Request: 126 ==> Response from server: MyServer1 |
| [java] Request: 127 ==> Response from server: MyServer1 |
| [java] Request: 128 ==> Response from server: MyServer2 |
| [java] Request: 129 ==> Response from server: MyServer2 |
| [java] Request: 130 ==> Response from server: MyServer2 |
| ...</div> |
| <p> |
| You can keep on shutting servers down like this. Client will get a response untill |
| you shutdown all listed servers. Once all servers are shutdown, the error sequence |
| is triggered and a fault message is sent to the client as follows. |
| </p> |
| <div class="consoleOutput">[java] COULDN'T SEND THE MESSAGE TO THE SERVER.</div> |
| <p> |
| Once a server is detected as failed, it will be added to the active servers |
| list again after 60 seconds (specified in <suspendDurationOnFailure> in |
| the configuration). Therefore, if you have restarted any of the stopped servers, |
| messages will be directed to the newly started server within 60 seconds. |
| </p> |
| </subsection> |
| </section> |
| <p><a href="../samples.html">Back to Catalog</a></p> |
| </body> |
| </document> |
