Tracking clustering issues

• The main clustering debug information can be customised using the following log4j setting (default value is INFO):  

log4j.logger.org.alfresco.enterprise.repo.cluster=info

• For a better control and more detailed clustering debug information, the following category can be configured:  

org.alfresco.enterprise.repo.cluster.core.ClusteringBootstrap

This controls clustering initialisation and shutdown. It provides INFO level startup and shutdown messages. It also provides WARN level messages, if clustering is disabled or an invalid 5.2 license is installed.

Here is an example output:

12:38:38,769 INFO [org.alfresco.enterprise.repo.cluster.core.ClusteringBootstrap] Cluster started, name:
      MainRepository-35ee3b27-0276-4224-9613-3fd8089c6e11
12:38:38,776 INFO [org.alfresco.enterprise.repo.cluster.core.ClusteringBootstrap] Current cluster
      members: 
    10.248.10.205:5701 (hostname: node1.alf.example.com)
    10.208.63.40:5701 (hostname: node2.alf.example.com)    

• When a cluster member leaves or joins, the following class generates an informative INFO level message:

org.alfresco.enterprise.repo.cluster.core.MembershipChangeLogger  

Here is an example output:

12:38:47,560 INFO [org.alfresco.enterprise.repo.cluster.core.MembershipChangeLogger] Member joined:
      10.65.41.64:5701 (hostname: node1.alf.example.com)
12:38:47,569 INFO [org.alfresco.enterprise.repo.cluster.core.MembershipChangeLogger] Current cluster
      members:
    10.208.63.40:5701 (hostname: solr.alf.example.com)
    10.248.10.205:5701 (hostname: node2.alf.example.com)
    10.65.41.64:5701 (hostname: node1.alf.example.com)

• An important aspect of clustering is caching. To log cache creation (for example, increase the cache related logging to DEBUG level), enable the following log categories:

  log4j.logger.org.alfresco.enterprise.repo.cluster.cache=DEBUG
  log4j.logger.org.alfresco.repo.cache=DEBUG

• The underlying clustering technology, Hazelcast, is configured to use log4j for logging. Therefore, you can configure logging for the whole Hazelcast top-level package, as shown:

log4j.logger.com.hazelcast=info

To increase logging from Hazelcast’s member joining mechanism, enable the following log category:

log4j.logger.com.hazelcast.impl.TcpIpJoiner=debug