Collecting Metrics in Knative

    Grafana dashboards are available for metrics collected directly with Prometheus.

    You can also set up the OpenTelemetry Collector to receive metrics from Knative components and distribute them to other metrics providers that support OpenTelemetry.

    is an open-source tool for collecting, aggregating timeseries metrics and alerting. It can also be used to scrape the OpenTelemetry Collector that is demonstrated below when Prometheus is used.

    Setting up Prometheus

    1. Install the by using Helm:

      Caution

      You will need to ensure that the helm chart has following values configured, otherwise the ServiceMonitors/Podmonitors will not work.

      2.   metricLabelsAllowlist:
      3.     - deployments=[app.kubernetes.io/name,app.kubernetes.io/component,app.kubernetes.io/instance]
      4. prometheus:
      5.   prometheusSpec:
      6.     serviceMonitorSelectorNilUsesHelmValues: false

    2. Apply the ServiceMonitors/PodMonitors to collect metrics from Knative.

      1. kubectl apply -f https://raw.githubusercontent.com/knative-sandbox/monitoring/main/servicemonitor.yaml

    3. Grafana dashboards can be imported from the .

    4. If you are using the Grafana Helm Chart with the Dashboard Sidecar configured, you can load the dashboards by applying the following configmap.

    To access the console in your web browser:

    1. Enter the command:

      1. kubectl port-forward -n default svc/prometheus-operated 9090

    2. Access the console in your browser via http://localhost:9090.

    OpenTelemetry is a CNCF observability framework for cloud-native software, which provides a collection of tools, APIs, and SDKs.

    You can use OpenTelemetry to instrument, generate, collect, and export telemetry data. This data includes metrics, logs, and traces, that you can analyze to understand the performance and behavior of Knative components.

    OpenTelemetry allows you to easily export metrics to multiple monitoring services without needing to rebuild or reconfigure the Knative binaries.

    Understanding the collector

    The collector provides a location where various Knative components can push metrics to be retained and collected by a monitoring service.

    In the following example, you can configure a single collector instance using a ConfigMap and a Deployment.

    Tip

    Caution

    The Grafana dashboards at don’t work with metrics scraped from OpenTelemetry Collector.

    1. Create a Deployment, Service, and ConfigMap for the collector by entering the following command:

    2. Update the ConfigMaps in the Knative Serving and Eventing namespaces, by entering the follow command:

      1. kubectl patch --namespace knative-serving configmap/config-observability \
      2.   --type merge \
      3.   --patch '{"data":{"metrics.backend-destination":"opencensus","metrics.request-metrics-backend-destination":"opencensus","metrics.opencensus-address":"otel-collector.metrics:55678"}}'
      4. kubectl patch --namespace knative-eventing configmap/config-observability \
      5.   --type merge \
      6.   --patch '{"data":{"metrics.backend-destination":"opencensus","metrics.opencensus-address":"otel-collector.metrics:55678"}}'

    Verify the collector setup

    1. You can check that metrics are being forwarded by loading the Prometheus export port on the collector, by entering the following command:

    2. Fetch http://localhost:8889/metrics to see the exported metrics.