title: Clustering Openfire 3.7.1
body: <p>I am trying for clustering openfire 3.7.1, but still not succeed and don't know what the problem is. Here are the steps:</p>
  
  <ul>
  <li>First, I install Clustering Plugin 1.2.0 from Plugins menu.</li>
  <li>Then I go to <em>Server -> Server Manager -> Clustering</em> menu and got <em>java.lang.NoClassDefFoundError: com/tangosol/net/Invocable</em> exception. Searching on the forum, I found that Clustering Plugin needs Oracle Coherence. So I download Oracle Coherence v3.4.2 and copy all jar files from lib dir into openfire lib dir. Then I restart openfire and now clustering menu seems ok, no exception occurred.</li>
  <li>I try to enable clustering from clustering menu. It states that enabling clustering may take 30 seconds. But after clicking the <em>Save settings</em> button, the process won't stop even after 10 minutes. So I stopped the process and restart openfire.</li>
  <li>I login again and everything seems good. Accessing again the Clustering menu, it shows that the clustering is enabled and there is 1 node listed and running. But when I click the nodes link, it does nothing. Also when I try to access 'Users/Group' menu, it shows HTTP ERROR 500 with <em>org.jivesoftware.util.cache.DefaultCache cannot be cast to com.jivesoftware.util.cache.ClusteredCache</em> exception.</li>
  </ul>
  
  <p>My machine specs are:</p>
  
  <ul>
  <li>Ubuntu 12.04</li>
  <li>Openfire 3.7.1</li>
  <li>Core i5 with 8 GB memory.</li>
  </ul>