telemetrysample

README

Telemetry Sample

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 (see Logs and Metrics for more information). This sample also creates a dedicated Prometheus instances rather than using the one that is installed by default as a showcase of installing dedicated Prometheus instances.

Prerequisites

1. Install Knative Serving
2. Install docker

Setup

Build the app container and publish it to your registry of choice:

REPO="gcr.io/<your-project-here>"

# Build and publish the container, run from the root directory.
docker build \
  --build-arg SAMPLE=telemetrysample \
  --tag "${REPO}/sample/telemetrysample" \
  --file=sample/Dockerfile.golang .
docker push "${REPO}/sample/telemetrysample"

# Replace the image reference with our published image.
perl -pi -e "s@github.com/knative/serving/sample/telemetrysample@${REPO}/sample/telemetrysample@g" sample/telemetrysample/*.yaml

# Deploy the Knative Serving sample
kubectl apply -f sample/telemetrysample/

Exploring

Once deployed, you can inspect the created resources with kubectl commands:

# This will show the route that we created:
kubectl get route -o yaml

# This will show the configuration that we created:
kubectl get configurations -o yaml

# This will show the Revision that was created by our configuration:
kubectl get revisions -o yaml

To access this service via curl, we first need to determine its ingress address:

watch kubectl get ingress
NAME                                 HOSTS                     ADDRESS   PORTS     AGE
telemetrysample-route-ela-ingress   telemetrysample.myhost.net             80        14s

Once the ADDRESS gets assigned to the cluster, you can run:

# Put the Ingress Host name into an environment variable.
export SERVICE_HOST=`kubectl get route telemetrysample-route -o jsonpath="{.status.domain}"`

# Put the Ingress IP into an environment variable.
export SERVICE_IP=`kubectl get ingress telemetrysample-route-ela-ingress -o jsonpath="{.status.loadBalancer.ingress[*]['ip']}"`

# Curl the Ingress IP "as-if" DNS were properly configured.
curl --header "Host:$SERVICE_HOST" http://${SERVICE_IP}
Hello World!

Generate some logs to STDOUT and files under /var/log in Json or plain text formats.

curl --header "Host:$SERVICE_HOST" http://${SERVICE_IP}/log
Sending logs done.

Accessing logs

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

Accessing per request traces

You can access to per request traces from Zipkin UI - see Logs and Metrics 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,prometheus=test --output=jsonpath="{.items[0].metadata.name}") 9090

Then browse to http://localhost:9090.

Cleaning up

To clean up the sample service:

kubectl delete -f sample/telemetrysample/