Author: chathura_ce
Date: Fri May 18 05:50:59 2007
New Revision: 539435
URL: http://svn.apache.org/viewvc?view=rev&rev=539435
Log:
Added documentation for session affinity based load balancing using client
initiated sessions.
This includes both load balancing among single servers and failover groups.
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=539435&r1=539434&r2=539435
==============================================================================
--- webservices/synapse/trunk/java/src/site/resources/Synapse_Samples.html
(original)
+++ webservices/synapse/trunk/java/src/site/resources/Synapse_Samples.html Fri
May 18 05:50:59 2007
@@ -1267,7 +1267,7 @@
<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
+installation directory>/samples/axis2Server/src/LoadbalanceFailoverService
directory and running ant.</p>
<p>Start three instances of sample Axis2 server on HTTP ports 9001, 9002 and
@@ -1418,6 +1418,232 @@
<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>
+
+<p></p>
+
+<p>Sample 56:</p>
+<pre><!-- Demontrates session affinity load balancing between 3 endpoints.
We are using client
+ initiated session for this sample. -->
+<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 -->
+ <strong><session
type="simpleClientSession"/></strong>
+
+ <loadbalance>
+ <endpoint>
+ <address
uri="http://localhost:9001/soap/LBService1">
+ <enableAddressing/>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9002/soap/LBService1">
+ <enableAddressing/>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9003/soap/LBService1">
+ <enableAddressing/>
+ </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 load balancing with session affinity
+using client initiated sessions</strong></p>
+
+<p><strong>Pre-Requisites:</strong></p>
+
+<p>Start Synapse with sample configuration 54 (i.e. synapse 54).</p>
+
+<p>Deploy the LoadbalanceFailoverService and start three instances of the
+sample Axis2 server as in sample 54. </p>
+
+<p></p>
+
+<p>Above configuration is same as the load balancing configuration in sample
+54, except that the session type is specified as "simpleClientSession". This
+is a client initiated session, which means that the client generates the
+session identifier and send it to with each request. In this sample session
+type, client adds a SOAP header named ClientID containing the identifier of
+the client. Synapse binds this ID with a server on the first request and
+sends all seccessive requests containing that ID to the same server. Now
+switch to samples/axis2Client directory and run the client using the
+following command to check this in action.</p>
+<pre>ant loadbalancefailover -Dmode=session</pre>
+
+<p>In the session mode, client continuesly sends requests with three diferent
+client (session) IDs. One ID is selected among these three IDs for each
+request randomly. Then client prints the session ID with the responded server
+for each request. Client output for the first 10 requests are shown below.</p>
+<pre>[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
+... </pre>
+
+<p>You can see that session number 0 is always directed to the server named
+MyServer1. That means session number 1 is bound to MyServer3. Similarly
+session 1 and 2 are bound to MyServer3 and MyServer2 respectively. </p>
+
+<h2>Sample 57:</h2>
+<pre><!-- Demontrates the session affinity load balancing between fail over
endpoints. If endpoint servers
+maintain session specific data, such data have to replicated among the
failover endpoints. -->
+<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 -->
+ <strong><session
type="simpleClientSession"/></strong>
+
+ <loadbalance>
+ <endpoint>
+ <failover>
+ <endpoint>
+ <address
uri="http://localhost:9001/soap/LBService1">
+ <enableAddressing/>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9002/soap/LBService1">
+ <enableAddressing/>
+ </address>
+ </endpoint>
+ </failover>
+ </endpoint>
+ <endpoint>
+ <failover>
+ <endpoint>
+ <address
uri="http://localhost:9003/soap/LBService1">
+ <enableAddressing/>
+ </address>
+ </endpoint>
+ <endpoint>
+ <address
uri="http://localhost:9004/soap/LBService1">
+ <enableAddressing/>
+ </address>
+ </endpoint>
+ </failover>
+ </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 session affinity based load balancing
+with failover capability</strong></p>
+
+<p><strong>Pre-Requisites:</strong></p>
+
+<p>Start Synapse with sample configuration 57 (i.e. synapse -sample 57).</p>
+
+<p>Deploy the LoadbalanceFailoverService and start four sample Axis2 servers
+on http ports 9001, 9002, 9003 and 9004 respectively (make sure to specify
+unconflicting https ports).</p>
+
+<p></p>
+
+<p>This configuration also uses "simpleClientSession" to bind sessions as in
+the previous sample. But failover endpoints are specified as the child
+endpoints of the load balance endpoint. Therefore sessions are bound to the
+failover 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 behavoir.</p>
+<pre>ant loadbalancefailover -Dmode=session</pre>
+
+<p>You can see a client output as shown below.</p>
+<pre>...
+[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
+...</pre>
+
+<p>Note that session 0 is always directed to MyServer1 and session 1 is
+directed to MyServer3. No requests are directed to MyServer2 and MyServer4 as
+they are kept as backups by failover endpoints. Now shutdown the server named
+MyServer1 while running the sample. You will observer 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>
+<pre>...
+[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
+...</pre>
<h2><a name="Sample60">Sample 60:</a></h2>
<pre><!-- demonstrates wsdl endpoint -->
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