Observability: Monitoring, logging, and tracing sample - Go

This sample runs a simple web server that makes calls to other in-cluster services and responds to requests with “Hello World!”. The purpose of this sample is to show generating metrics, logs and distributed traces. This sample also shows how to create a dedicated Prometheus instance rather than using the default installation.


  1. A Kubernetes cluster with Knative Serving installed and DNS configured.
  2. Check if Knative monitoring components are installed:

    kubectl get pods --namespace knative-monitoring
  1. Install Docker.
  2. Check out the code:

    go get -d github.com/knative/docs/docs/serving/samples/telemetry-go


Build the application container and publish it to a container registry:

  1. Move into the sample directory:

    cd $GOPATH/src/github.com/knative/docs
  2. Set your preferred container registry:

    export REPO="gcr.io/<YOUR_PROJECT_ID>"

This example shows how to use Google Container Registry (GCR). You will need a Google Cloud Project and to enable the Google Container Registry API.

  1. Use Docker to build your application container:

    docker build \
    --tag "${REPO}/docs/serving/samples/telemetry-go" \
    --file=docs/serving/samples/telemetry-go/Dockerfile .
  2. Push your container to a container registry:

    docker push "${REPO}/docs/serving/samples/telemetry-go"
  3. Replace the image reference path with our published image path in the configuration file (docs/serving/samples/telemetry-go/sample.yaml):

    • Manually replace: image: github.com/knative/docs/docs/serving/samples/telemetry-go with image: <YOUR_CONTAINER_REGISTRY>/docs/serving/samples/telemetry-go


    • Use run this command:

      perl -pi -e "s@github.com/knative/docs@${REPO}@g" docs/serving/samples/telemetry-go/sample.yaml

Deploy the Service

Deploy this application to Knative Serving:

kubectl apply --filename docs/serving/samples/telemetry-go/

Explore the Service

Inspect the created resources with the kubectl commands:

  • View the created Route resource:

    kubectl get route --output yaml
  • View the created Configuration resource:

    kubectl get configurations --output yaml
  • View the Revision that was created by the Configuration:

    kubectl get revisions --output yaml

Access the Service

To access this service via curl, you need to determine its ingress address.

  1. To determine if your service is ready:

    kubectl get ksvc --output yaml

When the service is ready, you’ll see the following fields reported as:

    status: "True"
    type: Ready
  url: http://telemetrysample-route.default.
  1. Make a request to the service to see the Hello World! message:

    curl http://telemetrysample-route.default.
  2. Make a request to the /log endpoint to generate logs to the stdout file and generate files under /var/log in both JSON and plain text formats:

    curl http://telemetrysample-route.default.

Access Logs

You can access to the logs from Kibana UI - see Logs for more information.

Access per Request Traces

You can access to per request traces from Zipkin UI - see Traces for more information.

Accessing Custom Metrics

You can see published metrics using Prometheus UI. To access to the UI, forward the Prometheus server to your machine:

kubectl port-forward $(kubectl get pods --selector=app=prometheus-test --output=jsonpath="{.items[0].metadata.name}") 9090

Then browse to http://localhost:9090.

Clean up

To clean up the sample service:

kubectl delete --filename docs/serving/samples/telemetry-go/