How to expose Kong metrics with Prometheus in K8s

I installed Kong using a Helm chart in Kubernetes — how do I expose Kong’s metrics to Prometheus?

1. Install Prometheus

   helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
   kubectl create ns monitoring
   helm upgrade -i prometheus prometheus-community/kube-prometheus-stack \
   --namespace monitoring \
   --set prometheus.prometheusSpec.serviceMonitorSelectorNilUsesHelmValues=false \
   --set fullnameOverride=prometheus
   kubectl get all -n monitoring

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   This Prometheus deployment is only for demo purposes and isn’t suitable for a production environment.

2. Install Kong

   The following parameter is required in values.yaml when installing Kong with the Helm chart:

   serviceMonitor:
     enabled: true

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   Set this parameter in values.yaml and install Kong.

   This configuration creates a ServiceMonitor object in the same namespace as Kong, as shown in the example below, which tells Prometheus how to scrape metrics from Kong.

   apiVersion: monitoring.coreos.com/v1
   kind: ServiceMonitor
   metadata:
     labels:
       app.kubernetes.io/instance: kong
       app.kubernetes.io/managed-by: Helm
       app.kubernetes.io/name: kong
       app.kubernetes.io/version: "3.14"
       helm.sh/chart: kong-2.41.0
     name: kong-kong
     namespace: kong
   spec:
     endpoints:
     - scheme: http
       targetPort: status
     - scheme: http
       targetPort: cmetrics
     jobLabel: kong
     namespaceSelector:
       matchNames:
       - kong
     selector:
       matchLabels:
         app.kubernetes.io/instance: kong
         app.kubernetes.io/managed-by: Helm
         app.kubernetes.io/name: kong
         app.kubernetes.io/version: "3.14"
         enable-metrics: "true"
         helm.sh/chart: kong-2.41.0

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3. Enable a global Prometheus plugin

   Enable the Prometheus plugin globally, then create Service and Route objects in Kong for proxy requests to upstreams. After that, send a few requests to Kong.

4. Forward port 9090 of the Prometheus Kubernetes service to localhost and check the metrics

   # Execute command to port forward 9090 port of the Prometheus K8S SVC to localhost
   kubectl port-forward service/prometheus-prometheus -n monitoring 9090:9090

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   Now you can access http://localhost:9090/ to open the Prometheus dashboard. You can see Kong’s metrics on the Prometheus dashboard.