Tomcat Applications Test

The Manager element on the Tomcat server represents the session manager that will be used to create and maintain HTTP sessions as requested by the associated web application. A session state is maintained for a period, typically starting with user interactions and ending with last interaction.

Besides memory management, manager also looks into various aspects including CPU usage, network load that large sessions introduce. The scalability and performance of any web based application depends upon how well HTTP sessions are transmitted and managed over network.

An application must guarantee that a user's session state is properly maintained in order to exhibit correct behavior for that user. The Tomcat Applications test closely monitors the state of sessions to every application on the Tomcat server.

Target of the test : A Tomcat Server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every application on the Tomcat server being monitored.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the host for which this test is to be configured.

Port

Refers to the port at which the specified host listens to.

Measurement Mode

This test can extract metrics from Tomcat using either of the following mechanisms:

  • By deploying the egtomcat.war file in the <EG_INSTALL_DIR>\lib directory of the eG agent host on the Tomcat server;
  • By contacting the Java runtime (JRE) of Tomcat via JMX

To configure the test to use egtomcat.war file, first select the War file option. Then, refer to the How does eG Enterprise Monitor Tomcat Servers? to know how to deploy the WAR file on the target Tomcat server.

On the other hand, if you want the test to use JMX instead, then first, select the JMX option. Then, follow the procedure detailed in the How does eG Enterprise Monitor Tomcat Servers? to configure the test to use jmx. By default, the JMX option is chosen here.

JMX Remote Port

This parameter appears only if the Measurement Mode is set to JMX. Here, specify the port at which the JMX listens for requests from remote hosts. Ensure that you specify the same port that you configured in the catalina.sh (or catalina.bat) file in the <CATALINA_HOME_DIR>/bin folder of the target Tomcat server (refer to the How does eG Enterprise Monitor Tomcat Servers? for more details).

JMX User, JMX Password, and Confirm Password

These parameters appear only if the Measurement Mode is set to JMX. If JMX equires authentication only (but no security), then ensure that the JMX User and JMX Password parameters are configured with the credentials of a user with read-write access to JMX. To know how to create this user, refer to the How does eG Enterprise Monitor Tomcat Servers?. Confirm the password by retyping it in the Confirm Password text box.

JNDIName

This parameter appears only if the Measurement Mode is set to JMX. The JNDIName is a lookup name for connecting to the JMX connector. By default, this is jmxrmi. If you have registered the JMX connector in the RMI registery using a different lookup name, then you can change this default value to reflect the same. 

JMX Provider

This parameter appears only if the Measurement Mode is set to JMX. This test uses a JMX Provider to access the MBean attributes of the target Java application and collect metrics. Specify the package name of this JMX Provider here. By default, this is set to com.sun.jmx.remote.protocol.

SSL

This parameter appears only if the Measurement Mode is set to War File. Indicate Yes if the Tomcat server is SSL-enabled.

URL

This parameter appears only if the Measurement Mode is set to War File. Specify the URL of the managed Tomcat server to enable the test to connect to it and extract measures from it. The URL specification should be of the format: http://{TomcatIP}:{TomcatPort}.

UserName, Password, and Confirm Password

These parameters appear only if the Measurement Mode is set to War File. In the UserName text box, specify a name of a user who has been assigned the Manager role on the Tomcat server to be monitored; these users are typically allowed to control web applications deployed on the Tomcat server. Specify the Password of this user, and confirm the password by retyping it in the Confirm Password text box.

EncryptPass

This parameter appears only if the measurement modeis set to War File. Select Yes if you want to encrypt the password.

Timeout

Specify the duration (in seconds) for which this test should wait for a response from Tomcat. If there is no response from Tomcat beyond the configured duration, the test will timeout. By default, this is set to 240 seconds.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Active sessions

Indicates the sessions that are currently active.

Number

A high value for this measure is indicative of heavy load on the Tomcat server.

Max sessions

Indicates the maximum number of active sessions that can be allowed at one time on the Tomcat server.

Number

 

Expired sessions

Indicates the number of sessions that expired since the last measurement period.

Number

A large number of expired sessions could hint at the need to reset the TIMEOUT period for sessions on the Tomcat server.

Rejected sessions

Indicates the number of sessions that were rejected since the last measurement period.

Number

It is imperative to check if there is any loss of session state happening due to network congestion. Therefore, if the value of this measure is unusually high, the reasons behind the unusual occurrence would have to be investigated. You can also consider increasing the maximum active session count.