Author: chathura_ce
Date: Mon May 7 03:45:22 2007
New Revision: 535842
URL: http://svn.apache.org/viewvc?view=rev&rev=535842
Log:
Added documentation for load balancing and failover samples.
Modified:
webservices/synapse/trunk/java/src/site/resources/Synapse_Samples.html
Modified: webservices/synapse/trunk/java/src/site/resources/Synapse_Samples.html
URL:
http://svn.apache.org/viewvc/webservices/synapse/trunk/java/src/site/resources/Synapse_Samples.html?view=diff&rev=535842&r1=535841&r2=535842
==============================================================================
--- webservices/synapse/trunk/java/src/site/resources/Synapse_Samples.html
(original)
+++ webservices/synapse/trunk/java/src/site/resources/Synapse_Samples.html Mon
May 7 03:45:22 2007
@@ -1197,6 +1197,219 @@
</m0:request>
</m0:getQuote>0</pre>
+<h2>Sample 54: </h2>
+<pre><!-- demontrates simple session less load balancing between 3
endpoints -->
+<definitions xmlns="http://ws.apache.org/ns/synapse">
+
+ <sequence name="main" onError="errorHandler">
+ <in>
+ <send>
+ <endpoint>
+ <loadbalance>
+ <endpoint>
+ <address
uri="http://localhost:9001/soap/LBService1">
+ <enableAddressing/>
+
<suspendDurationOnFailure>60</suspendDurationOnFailure>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9002/soap/LBService1">
+ <enableAddressing/>
+
<suspendDurationOnFailure>60</suspendDurationOnFailure>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9003/soap/LBService1">
+ <enableAddressing/>
+
<suspendDurationOnFailure>60</suspendDurationOnFailure>
+ </address>
+ </endpoint>
+ </loadbalance>
+ </endpoint>
+ </send>
+ </in>
+
+ <out>
+ <!-- Send the messages where they have been sent (i.e. implicit
To EPR) -->
+ <send/>
+ </out>
+ </sequence>
+
+ <sequence name="errorHandler">
+
+ <makefault>
+ <code value="tns:Receiver"
xmlns:tns="http://www.w3.org/2003/05/soap-envelope"/>
+ <reason value="COULDN'T SEND THE MESSAGE TO THE SERVER."/>
+ </makefault>
+
+ <header name="To" action="remove"/>
+ <property name="RESPONSE" value="true"/>
+
+ <send/>
+ </sequence>
+
+</definitions></pre>
+
+<p><strong>Objective: Demonstrate the simple load balancing among set of
+endpoints</strong></p>
+
+<p><strong>Pre-Requisites:</strong></p>
+
+<p>Start Synapse with sample configuration 54. (i.e. synapse -sample 54)</p>
+
+<p>Deploy the LoadbalanceFailoverService by switching to <synapse
+installation directory>/samples/axis2Server/src/LoadbalanceFailoverServer
+directory and running ant.</p>
+
+<p>Start three instances of sample Axis2 server on HTTP ports 9001, 9002 and
+9003 and give some unique names to each server.</p>
+
+<p>Example commands to run sample Axis2 servers in Linux is listed below:</p>
+<pre>axis2Server.sh -http 9001 -https 9005 -name MyServer1
+axis2Server.sh -http 9002 -https 9006 -name MyServer2
+axis2Server.sh -http 9003 -https 9007 -name MyServer3</pre>
+
+<p>Now we are done with setting up the environment for load balance sample.
+Start the load balance and failover client using the following command:</p>
+<pre>ant loadbalancefailover -Di=100</pre>
+
+<p>This client sends 100 requests to the LoadbalanceFailoverService through
+Synapse. Synapse will distribute the load among the three endpoints mentioned
+in the configuration in round robin manner. LoadbalanceFailoverService
+appends the name of the server to the response, so that client can determine
+which server has processed the message. If you examine the console output of
+the client, you can see that requests are processed by three servers as
+follows:</p>
+<pre>[java] Request: 1 ==> Response from server: MyServer1
+[java] Request: 2 ==> Response from server: MyServer2
+[java] Request: 3 ==> Response from server: MyServer3
+[java] Request: 4 ==> Response from server: MyServer1
+[java] Request: 5 ==> Response from server: MyServer2
+[java] Request: 6 ==> Response from server: MyServer3
+[java] Request: 7 ==> Response from server: MyServer1
+...</pre>
+
+<p>Now run the client without the -Di=100 parameter to send infinite
+requests. While running the client shutdown the server named MyServer1. You
+can observe that requests are only distributed among MyServer2 and MyServer3
+after shutting down MyServer1. Console output before and after shutting down
+MyServer1 is listed below (MyServer1 was shutdown after request 63):</p>
+<pre>...
+[java] Request: 61 ==> Response from server: MyServer1
+[java] Request: 62 ==> Response from server: MyServer2
+[java] Request: 63 ==> Response from server: MyServer3
+[java] Request: 64 ==> Response from server: MyServer2
+[java] Request: 65 ==> Response from server: MyServer3
+[java] Request: 66 ==> Response from server: MyServer2
+[java] Request: 67 ==> Response from server: MyServer3
+...</pre>
+
+<p>Now restart MyServer1. You can observe that requets will be again sent to
+all three servers roughly after 60 seconds. This is because we have specified
+<suspendDurationOnFailure> as 60 seconds in the configuration.
+Therefore, load balance endpoint will suspend any failed child endpoint only
+for 60 seconds after detecting the failure. </p>
+
+<h2>Sample 55:</h2>
+<pre><!-- Demontrates failover sending among 3 endpoints. -->
+<definitions xmlns="http://ws.apache.org/ns/synapse">
+
+ <sequence name="main" onError="errorHandler">
+ <in>
+ <send>
+ <endpoint>
+ <failover>
+ <endpoint>
+ <address
uri="http://localhost:9001/soap/LBService1">
+ <enableAddressing/>
+
<suspendDurationOnFailure>60</suspendDurationOnFailure>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9002/soap/LBService1">
+ <enableAddressing/>
+
<suspendDurationOnFailure>60</suspendDurationOnFailure>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9003/soap/LBService1">
+ <enableAddressing/>
+
<suspendDurationOnFailure>60</suspendDurationOnFailure>
+ </address>
+ </endpoint>
+ </failover>
+ </endpoint>
+ </send>
+ </in>
+
+ <out>
+ <!-- Send the messages where they have been sent (i.e. implicit
To EPR) -->
+ <send/>
+ </out>
+ </sequence>
+
+ <sequence name="errorHandler">
+
+ <makefault>
+ <code value="tns:Receiver"
xmlns:tns="http://www.w3.org/2003/05/soap-envelope"/>
+ <reason value="COULDN'T SEND THE MESSAGE TO THE SERVER."/>
+ </makefault>
+
+ <header name="To" action="remove"/>
+ <property name="RESPONSE" value="true"/>
+
+ <send/>
+ </sequence>
+
+</definitions></pre>
+
+<p><strong>Objective: Demonstrate the failover sending</strong></p>
+
+<p><strong>Pre-Requisites:</strong></p>
+
+<p>Start Synapse with sample configuration 55 (i.e. synapse -sample 55)</p>
+
+<p>Deploy the LoadbalanceFailoverService and start three instances of sample
+Axis2 server as mentioned in sample 54.</p>
+
+<p></p>
+
+<p>Above configuration sends messages with the failover behavior. Initially
+the server at port 9001 is treated as primary and other two are treated as
+back ups. Messages are always directed only to the primary server. If the
+primary server has failed, 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>
+<pre>ant loadbalancefailover</pre>
+
+<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.</p>
+
+<p>The console output with MyServer1 shutdown after request 127 is listed
+below:</p>
+<pre>...
+[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
+...</pre>
+
+<p>You can keep on shutting down servers like this. Client will get a
+response till you shutdown all listed servers. Once all servers are shutdown,
+the error sequence is activated and a fault message is sent to the client as
+follows:</p>
+<pre>[java] COULDN'T SEND THE MESSAGE TO THE SERVER.</pre>
+
+<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 and shutdown all other servers,
+messages will be directed to the newly started server.</p>
+
<h1><a name="ProxyServices" id="ProxyServices">Proxy services</a></h1>
<h2><a name="Sample100">Sample 100:</a></h2>
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