13.2. Configuring Prometheus metrics monitoring for Decision Server on Red Hat OpenShift Container Platform

Procedure

1. In the DeploymentConfig object of your Decision Server deployment on OpenShift, set the PROMETHEUS_SERVER_EXT_DISABLED environment variable to false to enable the Prometheus extension. You can set this variable in the OpenShift web console or use the oc command in a command terminal:

   oc set env dc/<dc_name> PROMETHEUS_SERVER_EXT_DISABLED=false -n <namespace>

   If you have not yet deployed your Decision Server on OpenShift, then in the OpenShift template that you plan to use for your OpenShift deployment (for example, rhdm75-prod-immutable-kieserver.yaml), you can set the PROMETHEUS_SERVER_EXT_DISABLED template parameter to false to enable the Prometheus extension.

   If you are using the OpenShift Operator to deploy Decision Server on OpenShift, then in your Decision Server configuration, set the PROMETHEUS_SERVER_EXT_DISABLED environment variable to false to enable the Prometheus extension:

   apiVersion: app.kiegroup.org/v1
   kind: KieApp
   metadata:
     name: enable-prometheus
   spec:
     environment: rhpam-trial
     objects:
       servers:
       - env:
         - name: PROMETHEUS_SERVER_EXT_DISABLED
           value: "false"

2. Create a service-metrics.yaml file to add a service that exposes the metrics from Decision Server to Prometheus:

   apiVersion: v1
   kind: Service
   metadata:
     annotations:
       description: RHDM Prometheus metrics exposed
     labels:
       app: myapp-kieserver
       application: myapp-kieserver
       template: myapp-kieserver
       metrics: rhdm
     name: rhdm-app-metrics
   spec:
     ports:
       - name: web
         port: 8080
         protocol: TCP
         targetPort: 8080
     selector:
       deploymentConfig: myapp-kieserver
     sessionAffinity: None
     type: ClusterIP

3. In a command terminal, use the oc command to apply the service-metrics.yaml file to your OpenShift deployment:

   oc apply -f service-metrics.yaml

4. Create an OpenShift secret, such as metrics-secret, to access the Prometheus metrics on Decision Server. The secret must contain the "username" and "password" elements with Decision Server user credentials. For information about OpenShift secrets, see the Secrets chapter in the OpenShift Developer Guide.

5. Create a service-monitor.yaml file that defines the ServiceMonitor object. A service monitor enables Prometheus to connect to the Decision Server metrics service.

   apiVersion: monitoring.coreos.com/v1
   kind: ServiceMonitor
   metadata:
     name: rhdm-service-monitor
     labels:
       team: frontend
   spec:
     selector:
       matchLabels:
         metrics: rhdm
     endpoints:
       - port: web
         path: /services/rest/metrics
         basicAuth:
           password:
             name: metrics-secret
             key: password
           username:
             name: metrics-secret
             key: username

6. In a command terminal, use the oc command to apply the service-monitor.yaml file to your OpenShift deployment:

   oc apply -f service-monitor.yaml

   After you complete these configurations, Prometheus begins collecting metrics and Decision Server publishes the metrics to the REST API endpoint http://HOST:PORT/kie-server/services/rest/metrics.

   You can interact with your collected metrics in the Prometheus expression browser at http://HOST:PORT/graph, or integrate your Prometheus data source with a data-graphing tool such as Grafana.

   The host and port for the Prometheus expression browser location http://HOST:PORT/graph was defined in the route where you exposed the Prometheus web console when you installed the Prometheus Operator. For information about OpenShift routes, see the Routes chapter in the OpenShift Architecture documentation.

   図13.5 Prometheus expression browser with Decision Server metrics

   

   図13.6 Prometheus expression browser with Decision Server target

   

   図13.7 Grafana dashboard with Decision Server metrics for DMN models

   

   図13.8 Grafana dashboard with Decision Server metrics for solvers