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    12.06.2018 10:57:33  Web Technologies > Tomcat    

JKStatusManager - Tomcat cluster monitor / Apache mod_jk load balancer management

German version

The Apache webserver with mod_jk modul loaded can serve as a load balancer for a cluster of tomcat instances, distributes the work load of web applications.In most cases the java web applications will run on different Tomcat instances and multiple server machines.

Once the Apache load balancer and Tomcat cluster is configured there is a need for a monitoring and management tool. For this reason there is the JKStatusManager web application. With JkStatusManager it is possible to active manage the tomcat workers and mod_jk load balancer.

Below is a browser sreenshot of JkStatusManager at work and the associated Apache 'httpd.conf' file activation entry.


Apache httpd.conf settings

JkStatusManager Aufruf URL

With JkStatusManager the tomcat cluster worker can temporarily disabled for maintenance reasons e.g. software installations, updates or application reconfiguration.
To disable a tomcat instance in a cluster set the worker status to 'disabled'. Before doing some maintenance tasks be sure that there are no active sessions remains on this tomcat worker.The value 'disabled' means that no new further sessions will be created by the load balancer on this tomcat worker. If all sessions of the worker are finished or timed out the worker is cluster released and can be configured.

Similar Links:
  Tomcat Cluster with Apache Load Balancer
  Configure Sticky Sessions in a Tomcat Cluster
  Tomcat cluster session replication
  Multiple Tomcat instances on a server