After fooling around with other methods, we finally accepted the advice I got on the Wicket IRC channel and used Terracotta to cluster our Wicket-based apps running under Jetty. It turned out to be straightforward to implement. The first thing to do was to add the Terracotta dependencies to our pom.xml. [sourcecode language=”xml”] org.terracotta.session terracotta-session 1.1.1 org.terracotta terracotta-toolkit-1.1-runtime 2.0.0 [/sourcecode] Then you just need to add a Terracotta filter to the jetty WebAppContext as follows: [sourcecode language=”java”] FilterHolder tcFilterHolder = new FilterHolder(TerracottaJetty61xSessionFilter.class); tcFilterHolder.setInitParameter(“tcConfigUrl”, “terracotta:9510,terracotta2:9510”); context.addFilter(tcFilterHolder, “/*”, Handler.ALL); [/sourcecode] That’s it. Terracotta will cluster the session (in the example we’re using two terracotta servers called “terracotta” and “terracotta2” – a main server and a standby). We’re using a HAProxy load-balancer with[…]