Tomcat monitoring : Probe

Lambda Probe is a self sufficient webapplication, which helps to visualize various parameters of Apache Tomcat instance in real time. Lambda Probe is designed to work specifically with Tomcat so it is able to access far more information that is normally available to JMX agents. Here is a list of features available through Lambda Probe:

• Comprehensive JVM memory usage monitor.
• Display of deployed applications, their status, session count, session object count, context object count,
  datasource usage etc.
• Start, stop, restart, deploy and updeploy of applications
• Ability to view deployed JSP files
• Ability to compile all or selected JSP files at any time.
• Ability to pre-compile JSP files on application deployment.
• Ability to view auto-generated JSP servlets
• Display of list of sessions for a particular application
• Display of session attributes and their values for a particular application. Ability to remove session attributes.
• Ability to view application context attributes and their values.
• Ability to expire selected sessions
• Graphical display of datasource details including maximum number of connections, number of busy connections and configuration
  details
• Ability to group datasource properties by URL to help visualizing impact on the databases
• Ability to reset data sources in case of applications leaking connection
• Display of system information including System.properties, memory usage bar and OS details
• Display of JK connector status including the list of requests pending execution
• Real-time connector usage charts and statistics.
• Real-time cluster monitoring and clulster traffic charts
• Real time OS memory usage, swap usage and CPU utilisation monitoring
• Ability to show information about log files and download selected files
• Ability to tail log files in real time from a browser.
• Ability to interrupt execution of "hang" requests without server restart
• New! Ability to restart Tomcat/JVM via Java Serview Wrapper.
• Availability "Quick check"
• Support for DBCP,C3P0 and Oracl datasources
• Support for Tomcat 5.0.x and 5.5.x
• Support for Java 1.4 and Java 1.5
  

Availability "Quick check"

Using this feature you can almost definitively monitor Apache Tomcat availability. "Quick check" does the following:

• Scans all available datasources and generates maximum usage score
• Allocates 1MB of memory into byte array
• Creates and then deletes 10 files in temp directory

The check fails if either of the following is true

• At least one of the declared datasources is 100% used
• Memory allocation test generated OutOfMemory exception
• File creation test encountered an IOException
  

Lambda Probe also has XML version of "Quick check" for automated aplication monitoring tools.Now let's take a look at real screens, Applications:

All deployed applications could be observed on this screen as URL
links,
for more detailed information click on application link, which shows a
different application parameters, for instance session:


on this screen session could be destroyed, you could see size of different session attributes.
In addition you Probe has session attributes, context attributes and requests screens.

Deployment: very important screen, if you want to view most updated tomcat


Nice functionality especially for those who don't want to deploy/redeploy a new applications manually.
Logs: very important screen for tomcat maintenance, you could even download log, wrap lines, pause update and etc.


System: shows memory statistics, tomcat memory parameters, computer information, enable to force garbage collector

Connector status: different statistics and charts about connection, traffic volume and number of requests.