Getting Started

This guide explains how to use PodMonitor and ServiceMonitor objects to monitor targets for a sample application.

The Prometheus resource declaratively describes the desired state of a Prometheus deployment, while ServiceMonitor and PodMonitor resources describe the targets to be monitored by Prometheus.

Pre-requisites #

Before you begin, ensure that you have:

• A Kubernetes cluster with admin permissions
• A running Prometheus Operator (refer to the Installation page)
• A running Prometheus instance (refer to the Platform Guide)

Deploying a sample application #

First, let’s deploy a simple example application with 3 replicas which listens and exposes metrics on port 8080.

apiVersion: apps/v1 kind: Deployment metadata:  name: example-app spec:  replicas: 3  selector:  matchLabels:  app: example-app  template:  metadata:  labels:  app: example-app  spec:  containers:  - name: example-app  image: quay.io/brancz/prometheus-example-app:v0.5.0  ports:  - name: web  containerPort: 8080 

Using ServiceMonitors #

To monitor the application using a ServiceMonitor, we will begin by exposing the application with a Service object that selects all the Pods with the label app set to example-app and specify the port where the metrics are exposed.

kind: Service apiVersion: v1 metadata:  name: example-app  labels:  app: example-app spec:  selector:  app: example-app  ports:  - name: web  port: 8080 

Finally, we create a ServiceMonitor object that selects all Service objects with the app: example-app label. The ServiceMonitor object also has a team label (in this case team: frontend) to identify which team is responsible for monitoring the application/service.

apiVersion: monitoring.coreos.com/v1 kind: ServiceMonitor metadata:  name: example-app  labels:  team: frontend spec:  selector:  matchLabels:  app: example-app  endpoints:  - port: web 

Similarly, the Prometheus object defines which ServiceMonitors get selected with the spec.serviceMonitorSelector field.

apiVersion: monitoring.coreos.com/v1 kind: Prometheus metadata: name: prometheus spec: serviceAccountName: prometheus serviceMonitorSelector: matchLabels: team: frontend 

Using PodMonitors #

While ServiceMonitor requires a Service object, PodMonitor can bypass the service and find targets based on Pod labels. The spec.selector field in the PodMonitor resource specifies which Pods Prometheus should scrape.

apiVersion: monitoring.coreos.com/v1 kind: PodMonitor metadata:  name: example-app  labels:  team: frontend spec:  selector:  matchLabels:  app: example-app  podMetricsEndpoints:  - port: web 

Similarly, the Prometheus object defines which PodMonitors get selected with the spec.podMonitorSelector field.

apiVersion: monitoring.coreos.com/v1 kind: Prometheus metadata: name: prometheus spec: serviceAccountName: prometheus podMonitorSelector: matchLabels: team: frontend 

What’s Next #