The Apache Tomcat integration collects traffic-related metrics, such as thenumber of active sessions or network throughput. The integration also collectsaccess and Catalina logs. Access logs are parsed into a JSON payloadfocused on request details, whereas Catalina logs are parsed for generaldetails. Thetomcat receiver collects telemetry from the Tomcat server's JavaVirtual Machine (JVM) viaJMX.

For more information about Tomcat, see theApache Tomcat documentation.

Prerequisites

To collect Tomcat telemetry, you mustinstall the Ops Agent:

• For metrics, install version 2.9.0 or higher.
• For logs, install version 2.9.0 or higher.

This integration supports Tomcat versions 10.x and 9.0.x.

Configure your Tomcat instance

To expose a JMX endpoint, you must set thecom.sun.management.jmxremote.portsystem property when starting the JVM. We also recommend setting thecom.sun.management.jmxremote.rmi.port system property to the same port. Toexpose a JMX endpoint remotely, you must also set thejava.rmi.server.hostnamesystem property.

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

To set system properties by using command-line arguments, prepend the propertyname with-D when starting the JVM. For example, to setcom.sun.management.jmxremote.port to port8050, specify the following whenstarting the JVM:

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

Configure the Ops Agent for Tomcat

Following the guide toConfigure the OpsAgent, add the required elementsto collect telemetry from Tomcat instances, andrestart the agent.

Example configuration

The following commands create the configuration to collect and ingest telemetryfor Tomcat:

#ConfiguresOpsAgenttocollecttelemetryfromtheapp.Youmustrestarttheagentfortheconfigurationtotakeeffect.set-e#Checkifthefileexistsif[!-f/etc/google-cloud-ops-agent/config.yaml];then#Createthefileifitdoesn'texist.sudomkdir-p/etc/google-cloud-ops-agentsudotouch/etc/google-cloud-ops-agent/config.yamlfi#Createabackupoftheexistingfilesoexistingconfigurationsarenotlost.sudocp/etc/google-cloud-ops-agent/config.yaml/etc/google-cloud-ops-agent/config.yaml.bak#ConfiguretheOpsAgent.sudotee/etc/google-cloud-ops-agent/config.yaml >/dev/null <<EOFmetrics:receivers:tomcat:type:tomcatendpoint:service:jmx:rmi:///jndi/rmi://127.0.0.1:8050/jmxrmiservice:pipelines:tomcat:receivers:-tomcatlogging:receivers:tomcat_access:type:tomcat_accesstomcat_system:type:tomcat_systemservice:pipelines:tomcat:receivers:-tomcat_access-tomcat_systemEOF

For these changes to take effect, you must restart the Ops Agent:

Configure logs collection

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

To configure a receiver for yourtomcat_system logs, specify the followingfields:

To configure a receiver for yourtomcat_access logs, specify the followingfields:

What is logged

ThelogName is derived fromthe receiver IDs specified in the configuration. Detailed fields inside theLogEntryare as follows.

Thetomcat_system logs contain the following fields in theLogEntry:

Thetomcat_access logs contain the following fields in theLogEntry:

Configure metrics collection

To ingest metrics from Tomcat, you must create a receiver for the metricsthat Tomcat produces and then create a pipeline for the new receiver.

This receiver does notsupport the use of multiple instances in the configuration, for example, tomonitor multiple endpoints. All such instances write to the same time series,and Cloud Monitoring has no way to distinguish among them.

To configure a receiver for yourtomcat metrics, specify the followingfields:

What is monitored

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

Verify the configuration

This section describes how to verify that you correctly configured theTomcat receiver. It might take one or twominutes for the Ops Agent to begin collecting telemetry.

To verify that Tomcat logs are being sent toCloud Logging, do the following:

1. In the Google Cloud console, go to theLogs Explorer page:

   Go toLogs Explorer

   If you use the search bar to find this page, then select the result whose subheading isLogging.

2. Enter the following query in the editor, and then clickRun query:
   

   resource.type="gce_instance"(log_id("tomcat_system") OR log_id("tomcat_access"))

To verify that Tomcat metrics are being sent toCloud Monitoring, do the following:

1. In the Google Cloud console, go to theleaderboard Metrics explorer page:

   Go toMetrics explorer

   If you use the search bar to find this page, then select the result whose subheading isMonitoring.

2. In the toolbar of thequery-builder pane, select the button whose name is eithercode MQL orcode PromQL.
3. Verify thatPromQL is selectedin theLanguage toggle. The language toggle is in the same toolbar thatlets you format your query.
4. Enter the following query in the editor, and then clickRun query:
   

   {"workload.googleapis.com/tomcat.threads", monitored_resource="gce_instance"}

View dashboard

To view your Tomcat metrics, you must have a chart or dashboardconfigured.The Tomcat integration includes one or more dashboards for you.Any dashboards are automatically installed after you configure theintegration and the Ops Agent has begun collecting metric data.

You can also view static previews of dashboards withoutinstalling the integration.

To view an installed dashboard, do the following:

1. In the Google Cloud console, go to the Dashboards page:

   Go toDashboards

   If you use the search bar to find this page, then select the result whose subheading isMonitoring.

2. Select theDashboard List tab, and then choose theIntegrations category.
3. Click the name of the dashboard you want to view.

If you have configured an integration but the dashboard has not beeninstalled, then check that the Ops Agent is running. When there is nometric data for a chart in the dashboard, installation of the dashboard fails.After the Ops Agent begins collecting metrics, the dashboard is installedfor you.

To view a static preview of the dashboard, do the following:

1. In the Google Cloud console, go to the Integrations page:

   Go toIntegrations

   If you use the search bar to find this page, then select the result whose subheading isMonitoring.

2. Click theCompute Engine deployment-platform filter.
3. Locate the entry for Tomcat and clickView Details.
4. Select theDashboards tab to see a static preview. If the dashboard is installed, then you can navigate to it by clickingView dashboard.

For more information about dashboards in Cloud Monitoring, seeDashboards and charts.

For more information about using theIntegrations page, seeManage integrations.

Install alerting policies

Alerting policies instruct Cloud Monitoring to notify you whenspecified conditions occur.The Tomcat integration includes one or more alerting policies foryou to use.You can view and installthese alerting policies from theIntegrations page inMonitoring.

To view the descriptions of available alerting policies and install them, do the following:

1. In the Google Cloud console, go to the Integrations page:

   Go toIntegrations

   If you use the search bar to find this page, then select the result whose subheading isMonitoring.

2. Locate the entry for Tomcat and clickView Details.
3. Select theAlerts tab. This tab provides descriptions of available alerting policies and provides an interface for installing them.
4. Install alerting policies. Alerting policies need to know where to send notifications that the alert has been triggered, so they require information from you for installation. To install alerting policies, do the following:
   1. From the list of available alerting policies, select those that you want to install.

   2. In theConfigure notifications section, select one or more notification channels. You have the option to disable the use of notification channels, but if you do, then your alerting policies fire silently. You can check their status in Monitoring, but you receive no notifications.

      For more information about notification channels, seeManage notification channels.

   3. ClickCreate Policies.

For more information about alerting policies in Cloud Monitoring, seeIntroduction to alerting.

For more information about using theIntegrations page, seeManage integrations.

What's next

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