Apache Tomcat Monitoring

Tomcat server monitoring and performance management made easy with Site24x7 plugins.

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Efficient monitoring of your Apache Tomcat servers is essential as poor performance can have a direct influence on the end-user experience. With Site24x7 Tomcat plugin, get a detailed view of all the critical Tomcat service metrics in a single, intuitive dashboard.

This document details how to configure the Apache Tomcat plugin and the monitoring metrics for providing in-depth visibility into the performance, availability, and usage stats of Tomcat servers.

Monitoring Metrics

The performance metrics for Tomcat falls under three categories: thread pool metrics, overall memory metrics, and usage metrics for each memory pool.

Total number of threads

thread_count is critical for tracking the resource consumption. This helps to prevent bottlenecks and detect thread pool exhaustion.

Busy threads count and total number of threads allowed

Comparing the metrics thread_busy and thread_count with thread_allowed gives an idea on the resource consumption.

Bytes received and bytes sent

Relate the thread count metrics with the bytes_received and bytes_sent to know the capacity of your web server.

Total number of errors

error_count gives the number of errors per second on all request processors.

Number of requests

The request_count metric gives the number of requests per second across all request processors.

Free Memory

The free_memory shows the amount of heap space currently available to the Java Virtual Machine (JVM).

Maximum Memory

The max_memory is the maximum size of the heap space not including the permanent generation area.

Time taken for processing the request

The sum of request processing times across all requests handled by the request processors is shown under processing_time.

Total Memory

The total_memory is the memory currently allocated to the JVM heap space.

Usage stats of each memory pool

Data from the metric usage_"name of the memory pool" gives the user a quick look on the memory usage. This can help manage memory resources proactively and resolve downtimes in production.


  • Ensure the configured TOMCAT_USERNAME is rightly assigned to the manager-script role in the tomcat-users.xml file. The username and password provided should be given in the Tomcat script. Sample code:
    role rolename="manager-gui"
    role rolename="manager-script"
    role rolename="manager-jmx"
    role rolename="manager-status"
    role rolename="admin-script"
    role rolename="admin-gui"
    user username="admin" password="admin" roles="admin-gui,manager-script,manager-jmx,manager-status,admin-script,manager-gui”

Plugin Installation

  • Download and install the latest version of the Site24x7 Linux agent in the server where you plan to run the plugin. If it is installed successfully, you will see a Linux server monitor in the Site24x7 Control Panel. This confirms that the agent is able to communicate with our data center.
  • Download the tomcat_connector.py, tomcat_overallmemory.py or the tomcat_memorypool.py from our GitHub repository.
  • The default python path given in the plugin script is #!/usr/bin/python. If you wish to provide an alternate python path, replace the existing one preceded by the shebang character "#!".
  • Create a directory with the name 'tomcat_connector' or 'tomcat_overallmemory' or 'tomcat_memorypool', under Site24x7 Linux agent plugin directory '/opt/site24x7/monagent/plugins/' and place the plugin files in their respective folders.
The agent will automatically execute the plugin within five minutes and send performance data to the Site24x7 data center.

View Data in the Site24x7 Web Client

  1. Log in to Site24x7 and go to Server > Plugins > Name of Plugin Monitor.
  2. You will be able to view the performance charts on the various metrics for your Tomcat server.

Customize your Plugin

To add/delete an attribute, or change its unit, edit the Python script file and make the desired changes. Increment the plugin version and from the next consecutive data collection, the changes would be reflected.

Plugin Contribution

Feel free to contribute to our existing plugin and come up with suggestions or feedback on our Community.