This will be covered at our upcoming Tomcat Administration Training Course in August, but a quick note that the default for this setting is ‘false’ and this can complicate easy and seamless load balancing and high availability of Web apps developed in Java and served to the ‘Net through Tomcat Java Application Server software.
In either the WEB-INF/web.xml or the META-INF/context.xml for the Tomcat App that needs to be hosted through a cluster of Tomcat servers, ensure that you have the following option set in a Context:
< Context distributable="true" / >
(remove spaces around < > chars)
If you do that for a webapp already deployed in a running Tomcat Cluster, you’ll see output in catalina.out mentioning that the cluster is now running for that webapp and other session distribution information.
If you set that in a web.xml globally in a Tomcat itself, then you’ll need to restart that Tomcat to enable this.
If you’re interested in learn (much) more about Tomcats and their administration and clustering, then please contact ETC Australia for more information and details on the upcoming Tomcat Administration training course in August.
FYI,
Richard.