Monitoring Apache Tomcat

After you install the Instana host agent, the Apache Tomcat sensor is automatically installed and configured. You can view metrics that are related to Apache Tomcat in the Instana UI.

Supported information

Supported operating systems

The supported operating systems of the Tomcat sensor are consistent with host agent requirements, which can be checked in the Supported operating systems section of each host agent, such as Supported operating systems for Unix.

Supported versions

Instana supports monitoring metrics and configuration data for all versions of Apache Tomcat from 5.x to 11.x.

Supported client-side tracing

For this technology, Instana supports client-side tracing for the following language:

Optional configuration

Naming Tomcat

The Apache Tomcat sensor reads the Tomcat configuration file ServerInfo.properties and extracts the name for the Tomcat instances from it. This name is displayed in the Intana UI.

Optionally, you can change the name of the Tomcat instance within Instana by editing the Tomcat configuration file ServerInfo.properties.

To edit the configuration file for renaming the Tomcat instance, complete the following steps:

  1. Go to the following ServerInfo.properties file:
    CATALINA_BASE/lib/org/apache/catalina/util/ServerInfo.properties
  2. To change the name of the Tomcat instance, modify the value of the server.info field. See the following example:
    server.info=Apache Tomcat/7.0.x

Metrics collection

The Apache Tomcat sensor monitors the Apache Tomcat instance and collects the following metrics from it:

To view these metrics, complete the following steps:

  1. Select Infrastructure in the sidebar of the Instana UI.
  2. Click a specific monitored host. You can see the host dashboard with all the collected metrics and monitored processes.

Configuration data

The Apache Tomcat sensor collects the following configuration data from the Apache Tomcat instance:

  • Version
  • Home
  • Web Apps
  • Application Configuration
  • Connectors
  • Servlets
  • Executors
  • Data sources

Performance metrics

The Apache Tomcat sensor collects the following performance metrics from the Apache Tomcat instance:

Metric Description Granularity
Sessions
Session count The number of currently active sessions. 1 second
Requests The number of requests per second. 1 second
Average Response Times The average response time across all requests to a servlet (in milliseconds) per second. 1 second
Errors The number of erroneous requests per second. 1 second
Connectors
Thread count The number of threads that are currently assigned to a connector. 1 second
Busy threads The number of threads that are currently busy processing requests. 1 second
Max threads The maximum number of threads that a pool can contain. 1 second
Connection count The current number of connections that are handled by an endpoint. 1 second
Max connections The total number of concurrent connections that a server accepts and processes. 1 second
Executors
Thread count The current number of threads in a pool. 1 second
Queue size The number of request processing tasks that are currently enqueued in the queue of a thread pool. 1 second
Max threads The maximum number of threads that can be allocated or created in a pool. 1 second
Data sources
Active connections The current number of active connections that are allocated from a particular data source. 1 second
Max connections The maximum number of active connections that can be allocated at the same time. 1 second

Health Signatures

Each sensor has a curated knowledgebase of health signatures that are evaluated continuously against the incoming metrics. These health signatures are used to raise issues or incidents that depend on user impact.

Built-in events trigger issues or incidents based on failing health signatures on entities. Custom events trigger issues or incidents based on the thresholds of an individual metric of any entity.

For more information about built-events for the Apache Tomcat sensor, see Built-in events reference.

Tracing

Instana provides tracing support for Apache Tomcat. For more information, see Monitoring Java Virtual Machine.