Apache Tomcat mixin

The Apache Tomcat mixin is a set of configurable Grafana dashboards and alerts.

The Apache Tomcat mixin contains the following dashboards:

• Apache Tomcat overview
• Apache Tomcat hosts

and the following alerts:

• ApacheTomcatAlertsHighCpuUsage
• ApacheTomcatAlertsHighMemoryUsage
• ApacheTomcatAlertsHighRequestErrorPercent
• ApacheTomcatAlertsModeratelyHighProcessingTime

Default thresholds can be configured in config.libsonnet.

{
  _config+:: {
    ApacheTomcatAlertsCriticalCpuUsage: 80,  //%
    ApacheTomcatAlertsCriticalMemoryUsage: 80,  //%
    ApacheTomcatAlertsCriticalRequestErrorPercentage: 5,  //%
    ApacheTomcatAlertsWarningProcessingTime: 300,  //ms
  },
}

Apache Tomcat overview

The Apache Tomcat overview provides details on memory/cpu usage, traffic sent/received, request processing time, number of threads, and output logs for a Tomcat instance. To get Tomcat output logs, Promtail and Loki needs to be installed and provisioned for logs with your Grafana instance. The default Tomcat output log path is /var/log/tomcat*/catalina.out on Linux and C:\Program Files\Apache Software Foundation\Tomcat *.*\logs\catalina.out on Windows.

Tomcat output logs are enabled by default in the config.libsonnet and can be removed by setting enableLokiLogs to false. Then run make again to regenerate the dashboard:

{
  _config+:: {
    enableLokiLogs: false,
  },
}

Apache Tomcat hosts

The Apache Tomcat hosts dashboard provides details on number of sessions, session processing time, number of servlet requests, and servlet processing time.

Alerts overview

ApacheTomcatAlertsHighCpuUsage: The instance has a CPU usage higher than the configured threshold. ApacheTomcatAlertsHighMemoryUsage: The instance has a higher memory usage than the configured threshold. ApacheTomcatAlertsHighRequestErrorPercent: There are a high number of request errors. ApacheTomcatAlertsModeratelyHighProcessingTime: The processing time has been moderately high.

Install tools

go install github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb@latest
go install github.com/monitoring-mixins/mixtool/cmd/mixtool@latest

For linting and formatting, you would also need jsonnetfmt installed. If you have a working Go development environment, it's easiest to run the following:

go install github.com/google/go-jsonnet/cmd/jsonnetfmt@latest

The files in dashboards_out need to be imported into your Grafana server. The exact details will be depending on your environment.

prometheus_alerts.yaml needs to be imported into Prometheus.

Generate dashboards and alerts

Edit config.libsonnet if required and then build JSON dashboard files for Grafana:

make

For more advanced uses of mixins, see https://github.com/monitoring-mixins/docs.