monitoring-setting-up-metrics-collection.adoc

Setting up metrics collection

To use the metrics exposed by your service, you need to configure OpenShift Monitoring to scrape metrics from the /metrics endpoint. You can do this using a ServiceMonitor, a custom resource definition (CRD) that specifies how a service should be monitored, or a PodMonitor, a CRD that specifies how a pod should be monitored. The former requires a Service object, while the latter does not, allowing Prometheus to directly scrape metrics from the metrics endpoint exposed by a Pod.

This procedure shows how to create a ServiceMonitor for the service.

Prerequisites

• Log in as a cluster administrator or a user with the monitor-crd-edit role.

Procedure

1. Create a YAML file for the ServiceMonitor configuration. In this example, the file is called example-app-service-monitor.yaml.

2. Fill the file with the configuration for creating the ServiceMonitor:

   apiVersion: monitoring.coreos.com/v1
   kind: ServiceMonitor
   metadata:
     labels:
       k8s-app: prometheus-example-monitor
     name: prometheus-example-monitor
     namespace: ns1
   spec:
     endpoints:
     - interval: 30s
       port: web
       scheme: http
     selector:
       matchLabels:
         app: prometheus-example-app

   This configuration makes OpenShift Monitoring scrape the metrics exposed by the sample service deployed in "Deploying a sample service", which includes the single version metric.

3. Apply the configuration file to the cluster:

   $ oc apply -f example-app-service-monitor.yaml

   It will take some time to deploy the ServiceMonitor.

4. You can check that the ServiceMonitor is running:

   $ oc -n ns1 get servicemonitor
   NAME                         AGE
   prometheus-example-monitor   81m

Additional resources

See the Prometheus Operator API documentation for more information on ServiceMonitors and PodMonitors.