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Setting up session replication consists of the following steps:
More information regarding Tomcat Session Replication can be found at http://tomcat.apache.org
Session Replication
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Limitations
There are several caveats to using Session Replication with Yellowfin (or any Java web application). The two main downsides of Session Replication are processing overhead, and memory usage.
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It should be considered if this overhead is worth the added fail-safe functionality that it brings. If Session Replication is not used, and a node fails, a user’s session will be destroyed, but they'll be able to log in to another node to continue their work.
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Modifications to web.xml
The text “<distributable/>” needs to be added to the web.xml file on each node underneath the “<webapp>” line. For example:
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<web-app> <distributable/> <!-- System Event and Debug classes --> <listener> <listener-class>com.hof.servlet.SysSessionListener</listener-class> </listener> |
To enable session replication, add the following to the ClusterManagement servlet in the web.xml file.
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<init-param>
<param-name>SessionReplication</param-name>
<param-value>true</param-value>
</init-param>
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Modifications to server.xml
Changes need to be made to the server.xml file in the Yellowfin/appserver/conf directory.
Add the additional XML entry within the “<host>” XML block.
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<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/> |
The IP address “228.0.0.4” is a multicast address that session replication messages will be received on. This does not need to be modified, but a Linux/Unix server may need to register a valid multicast route to receive broadcasts on this address. This can be done by running the following command on the console:
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sudo route add -net 224.0.0.0 netmask 224.0.0.0 dev eth0 |
This syntax may be different for different flavours of Linux or Unnis. This example uses “eth0” as the network device that will be used for this route.
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Modifications to ROOT.xml
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