Apache Tomcat

The Apache Tomcat integration collects traffic-related metrics, such as the number of active sessions or network throughput. The integration also collects access and Catalina logs. Access logs are parsed into a JSON payload focused on request details, whereas Catalina logs are parsed for general details. The tomcat receiver collects telemetry from the Tomcat server's Java Virtual Machine (JVM) via JMX.

For more information about Apache Tomcat, see tomcat.apache.org.

Prerequisites

To collect and ingest Tomcat logs and metrics, you must install Ops Agent version 2.9.0 or higher.

This receiver supports Apache Tomcat versions 9.0.x and 10.x.

Configure your Tomcat instance

To expose a JMX endpoint, you must set the com.sun.management.jmxremote.port system property when starting the JVM. We also recommend setting the com.sun.management.jmxremote.rmi.port system property to the same port. To expose a JMX endpoint remotely, you must also set the java.rmi.server.hostname system property.

By default, these properties are set in a Tomcat deployment's tomcat-env.sh file.

To set system properties by using command-line arguments, prepend the property name with -D when starting the JVM. For example, to set com.sun.management.jmxremote.port to port 8050, specify the following when starting the JVM:

-Dcom.sun.management.jmxremote.port=8050

Configure the Ops Agent for Tomcat

Following the guide for Configuring the Ops Agent, add the required elements to collect logs and metrics from your Tomcat instances, and restart the agent.

Example configuration

The following command creates the configuration file to collect and ingest logs and metrics for Apache Tomcat and restarts the Ops Agent on Linux.

sudo tee /etc/google-cloud-ops-agent/config.yaml > /dev/null << EOF
logging:
  receivers:
    tomcat_system:
      type: tomcat_system
    tomcat_access:
      type: tomcat_access
  service:
    pipelines:
      tomcat:
        receivers:
          - tomcat_system
          - tomcat_access
metrics:
  receivers:
    tomcat:
      type: tomcat
  service:
    pipelines:
      tomcat_pipeline:
        receivers:
          - tomcat
EOF
sudo service google-cloud-ops-agent restart

Configure logs collection

To ingest logs from Tomcat, you must create receivers for the logs that Tomcat produces and then create a pipeline for the new receivers.

To configure a receiver for your tomcat_system logs, specify the following fields:

Field Default Description
type The value must be tomcat_system.
include_paths [/opt/tomcat/logs/catalina.out] The log files to read. A wild card, (*), can be used in the paths; for example, /var/log/apache*/*.log.
exclude_paths The log files to exclude, if include_paths contains a glob or directory.


To configure a receiver for your tomcat_access logs, specify the following fields:

Field Default Description
type The value must be tomcat_access.
include_paths [/opt/tomcat/logs/localhost_access_log.*.txt] The log files to read.
exclude_paths [] The log files to exclude, if include_paths contains a glob or directory.

What is logged

The logName of the tomcat_system and tomcat_access logs are derived from the receiver IDs specified in the configuration. Detailed fields inside the LogEntry are as follows.

tomcat_system
These logs contain the following fields in the LogEntry:

Field Type Description
timestamp string (Timestamp) Time the request was received
jsonPayload.module string Module of tomcat where the log originated
jsonPayload.source string Source from where the log originated
jsonPayload.message string Log message, including detailed stack trace when provided
severity string (LogSeverity) Log entry level (translated)

tomcat_access
These logs contain the following fields in the LogEntry:

Field Type Description
httpRequest.protocol string Protocol used for the request
httpRequest.referer string Contents of the Referer header
httpRequest.requestMethod string HTTP method
httpRequest.requestUrl string Request URL (typically just the path part of the URL)
httpRequest.responseSize string (int64) Response size
httpRequest.status number HTTP status code
httpRequest.userAgent string Contents of the User-Agent header
jsonPayload.host string Contents of the Host header
jsonPayload.user string Authenticated username for the request
timestamp string (Timestamp) Time the request was received

Configure metrics collection

To collect metrics from Tomcat, you must create a receiver for Tomcat metrics and then create a pipeline for the new receiver. To configure a receiver for your Tomcat metrics, specify the following fields:

Field Default Description
type The value must be tomcat.
endpoint localhost:8050 The JMX Service URL or host and port used to construct the service URL. This value must be in the form of service:jmx:<protocol>:<sap> or host:port. Values in host:port form are used to create a service URL of service:jmx:rmi:///jndi/rmi://<host>:<port>/jmxrmi.
collect_jvm_metrics true Configures the receiver to also collect the supported JVM metrics.
username The configured username if JMX is configured to require authentication.
password The configured password if JMX is configured to require authentication.
collection_interval 60s A time.Duration value, such as 30s or 5m.

What is monitored

The following table provides the list of metrics that the Ops Agent collects from the Tomcat instance.

Metric type 
Kind, Type
Monitored resources
Labels
workload.googleapis.com/tomcat.errors
CUMULATIVEINT64
gce_instance
proto_handler
workload.googleapis.com/tomcat.max_time
GAUGEINT64
gce_instance
proto_handler
workload.googleapis.com/tomcat.processing_time
CUMULATIVEINT64
gce_instance
proto_handler
workload.googleapis.com/tomcat.request_count
CUMULATIVEINT64
gce_instance
proto_handler
workload.googleapis.com/tomcat.sessions
GAUGEDOUBLE
gce_instance
 
workload.googleapis.com/tomcat.threads
GAUGEINT64
gce_instance
proto_handler
workload.googleapis.com/tomcat.traffic
CUMULATIVEINT64
gce_instance
proto_handler
direction

Sample dashboard

You can view the metrics from this integration using a sample Cloud Monitoring dashboard. Complete the Installing sample dashboards procedures to import the Tomcat GCE Overview dashboard from the Sample library and view charts that display your Apache Tomcat metrics.

Verify the configuration

You can use the Logs Explorer and Metrics Explorer to verify that you correctly configured the Tomcat receiver. It might take one or two minutes for the Ops Agent to begin collecting logs and metrics.

To verify the logs are ingested, go to the Logs Explorer and run the following query to view the Tomcat logs:

resource.type="gce_instance"
logName=("projects/PROJECT_ID/logs/tomcast_system" OR "projects/PROJECT_ID/logs/tomcat_access")


To verify the metrics are ingested, go to Metrics Explorer and run the following query in the MQL tab.

fetch gce_instance
| metric 'workload.googleapis.com/tomcat.sessions'
| align rate(1m)
| every 1m

What's next

For a walkthrough on how to use Ansible to install the Ops Agent, configure a third-party application, and install a sample dashboard, see the Install the Ops Agent to troubleshoot third-party applications video.