Apache Tomcat OpenTelemetry Assets

Apache Tomcat is a Java servlet container and web server that implements the Jakarta Servlet, Jakarta Server Pages, and WebSocket specifications, widely deployed as the runtime for Java web applications.

These assets provide dashboards, alert rules, and SLO templates for monitoring Apache Tomcat via the OpenTelemetry Prometheus receiver scraping a Prometheus JMX Exporter, covering request processing, thread pool and connection management, JVM memory and garbage collection, session lifecycle, and OS-level resource utilization.

The Apache Tomcat OpenTelemetry assets have been tested with:

• OpenTelemetry prometheusreceiver v0.144.0 from OpenTelemetry Collector Contrib.
• Apache Tomcat/9.0.115

You need Elasticsearch for storing and searching your data and Kibana for visualizing and managing it. You can use our hosted Elasticsearch Service on Elastic Cloud, which is recommended, or self-manage the Elastic Stack on your own hardware.

You must attach the Prometheus JMX Exporter Java agent to your Tomcat JVM process. This agent exposes Tomcat's JMX MBeans as Prometheus metrics on an HTTP endpoint (port 9404 by default).

1. Download the JMX Exporter agent JAR:

curl -L -o jmx_prometheus_javaagent.jar https://repo1.maven.org/maven2/io/prometheus/jmx/jmx_prometheus_javaagent/1.0.1/jmx_prometheus_javaagent-1.0.1.jar
		

2. Create a JMX Exporter configuration file (jmx_exporter_config.yaml). A minimal configuration that exposes all Catalina and JVM MBeans:

rules:
  - pattern: ".*"
		

3. Add the agent to your Tomcat startup by setting CATALINA_OPTS in setenv.sh (or equivalent):

export CATALINA_OPTS="$CATALINA_OPTS -javaagent:/path/to/jmx_prometheus_javaagent.jar=9404:/path/to/jmx_exporter_config.yaml"
		

4. Verify the metrics endpoint is accessible:

curl http://localhost:9404/metrics
		

You should see Prometheus-formatted metrics including Catalina_* and java_lang_* prefixed lines.

Configure your OpenTelemetry Collector (or EDOT Collector) with the following configuration to scrape Tomcat JMX Exporter metrics and export them to Elasticsearch.

Placeholders:

• <TOMCAT_HOST> — Hostname or IP address of the Tomcat instance running the JMX Exporter (e.g. localhost)
• <JMX_EXPORTER_PORT> — Port the JMX Exporter is listening on (e.g. 9404)
• <ES_ENDPOINT> — Your Elasticsearch endpoint URL (e.g. https://my-deployment.es.us-central1.gcp.cloud.es.io:443)
• ${env:ES_API_KEY} — Elasticsearch API key, set via the ES_API_KEY environment variable

receivers:
  prometheus/tomcat:
    config:
      scrape_configs:
        - job_name: "tomcat"
          scrape_interval: 10s
          metrics_path: /metrics
          params:
            format: [prometheus]
          scheme: http
          static_configs:
            - targets: ["<TOMCAT_HOST>:<JMX_EXPORTER_PORT>"]

processors:
  resource/dataset:
    attributes:
      - key: data_stream.dataset
        value: tomcat
        action: upsert

exporters:
  elasticsearch/otel:
    endpoint: <ES_ENDPOINT>
    api_key: ${env:ES_API_KEY}
    mapping:
      mode: otel
    logs_dynamic_index:
      enabled: true
    metrics_dynamic_index:
      enabled: true

service:
  pipelines:
    metrics:
      receivers: [prometheus/tomcat]
      processors: [resource/dataset]
      exporters: [elasticsearch/otel]
		

Refer to the Prometheus receiver documentation for details on the receiver configuration. The available Tomcat metrics are defined by the Prometheus JMX Exporter configuration and the JMX MBeans exposed by your Tomcat instance, including Catalina_* (request processing, thread pools, sessions, servlets) and java_lang_* (JVM memory, garbage collection, threading, OS resources) metric families.

This integration includes one or more Kibana dashboards that visualizes the data collected by the integration. The screenshots below illustrate how the ingested data is displayed.

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