posted by MSacks on March 17, 2010 06:24 AM

There are three schools of thought on how to achieve the same task of managing a large production Tomcat infrastructure: distributed command-line solutions,  custom tools using Java Management Extensions (JMX), and full-blown commercial software suites designed for managing Tomcat specifically.  All of the methods and utilities for managing Tomcat have their own respective tradeoffs of elegance, simplicity, manageability, and cost.

Tomcat Manager Application

The Tomcat Manager application is an excellent utility for managing Tomcat server. It has built-in support for deploying and un-deploying applications, reloading applications, gathering statistics about the JVM and Web application, as well as starting and stopping applications. IT even includes a Web-based JMX proxy where a user can modify and query MBeans through the manager application.

Where it falls short is that it primarily only supports functions for performing management operations at the servlet container level and above. It doesn’t allow a user to restart, start or stop the JVM that the Tomcat instance runs on from this Web interface and doesn’t have a built-in method for managing groups of Tomcat servers.

1) Command Line and Scripted Interfaces

The simplest method is using ssh-keys and shell/Python/Ruby/Groovy scripts, which requires little effort to implement, but lacks in elegance. There are a number of service wrappers that support automatic restarts on failure, schedule restarts and taking thread dumps on failure, but they don’t come with a good interface through being managed remotely by a Java standard such as JMX.

Many institutions implement homegrown or scripted solutions for managing large Tomcat infrastructures. When dealing with anything beyond 10 Tomcat servers, it becomes tedious to log into each host and start and stop each Tomcat instance.

Many solutions exist for running a distributed command against a large group of Tomcat clusters. Some organizations set up SSH keys on all hosts and use a scripted or CGI Web interface to send a single command to a large group of servers; however, when dealing with thousands of hosts, installing the keys can become a tedious task, and without a configuration management utility, such as Puppet or Cfengine this can consume a large amount of time to perform.

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