Prometheus Stack Operator: Not Scraping Metrics from Cluster Application
In this article, we will explore the issue of the Prometheus Stack Operator not scraping metrics from a cluster application. We will cover key concepts related to this topic, including subtitles and paragraphs. Properly formatted code blocks will also be included to illustrate important points.
Introduction
Prometheus is an open-source systems monitoring and alerting toolkit. It is widely used for monitoring Kubernetes clusters and containerized applications. The Prometheus Stack Operator is a tool that simplifies the deployment and management of the Prometheus Stack on Kubernetes. However, there might be instances where the Prometheus Stack Operator fails to scrape metrics from a cluster application.
Prerequisites
To follow along with this article, you should have a basic understanding of Kubernetes and Prometheus. You should also have a Kubernetes cluster up and running, with the Prometheus Stack Operator installed. Additionally, you should have a cluster application that you want to monitor using Prometheus.
Verifying the Installation of the Prometheus Stack Operator
Before proceeding, you need to make sure that the Prometheus Stack Operator has been installed correctly. You can verify its installation using the following command:
kubectl get pods -n
Here, prometheus-operator, prometheus, and alertmanager.
Checking Prometheus Configuration
If the Prometheus Stack Operator is running but not scraping metrics from your cluster application, the first step is to check the Prometheus configuration. You can access the Prometheus configuration by port-forwarding to the Prometheus pod.
kubectl port-forward -n 9090
Here,
In the Prometheus UI, click on the Status tab and then the Config button. Check if the service discovery for your cluster application is enabled and configured correctly.
Checking the Service Monitor
If the Prometheus configuration is correct, the next step is to check the service monitor for your cluster application. A service monitor is a Kubernetes custom resource that defines how Prometheus should scrape metrics from a service. You can list all the service monitors using the following command:
kubectl get servicemonitors -n
Check if there is a service monitor for your cluster application. If there isn't, you need to create one. Here is an example service monitor for a cluster application:
apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
name: my-cluster-app
namespace:
spec:
endpoints:
- port: metrics
path: /metrics
selector:
matchLabels:
app: my-cluster-app
Here, my-cluster-app with the label selector for your cluster application. Ensure that the port and path match the endpoint where your cluster application exposes its metrics.
Verifying Metrics Collection
Once you have created the service monitor, Prometheus will start scraping metrics from your cluster application. You can verify if metrics are being collected by checking the Prometheus UI again.
kubectl port-forward -n 9090
Access Prometheus at
- Verified the installation of the Prometheus Stack Operator
- Checked the Prometheus configuration
- Checked the service monitor
- Verified metrics collection