Install Prometheus on kubernetes

If you're using Kubernetes to manage your containerized workloads, you may want to consider installing Prometheus as a StatefulSet. In this article, we'll show you how to do just that and optimize your setup for better performance using VolumeClaimTemplates.

Prometheus is an open-source monitoring system and time-series database designed for collecting, storing, and querying metrics data. It was developed by SoundCloud and is now a part of the Cloud Native Computing Foundation (CNCF). Prometheus provides a flexible and powerful platform for monitoring and alerting on metrics data from various sources, including containers, applications, and system resources. It uses a pull-based model to scrape metrics data from endpoints and stores it in a time-series database. Prometheus also provides a query language called PromQL that allows users to retrieve and analyze metrics data. It can be integrated with other tools in the Kubernetes ecosystem, such as Grafana and Alertmanager, to create a complete monitoring and alerting solution. Overall, Prometheus is a popular and powerful tool for monitoring and analyzing the performance and health of modern applications and infrastructure.

Create a ConfigMap

The first step is to create a ConfigMap that will hold the configuration for Prometheus. This YAML file will create a ConfigMap that you can use as a starting point:

apiVersion: v1
kind: ConfigMap
metadata:
  name: prometheus-config
data:
  prometheus.yml: |-
    global:
      scrape_interval: 15s
      evaluation_interval: 15s
    scrape_configs:
      - job_name: 'kubernetes-apiservers'
        kubernetes_sd_configs:
        - role: endpoints
          namespaces:
            names:
            - kube-system
        scheme: https
        tls_config:
          ca_file: /var/run/secrets/kubernetes.io/serviceaccount/ca.crt
        bearer_token_file: /var/run/secrets/kubernetes.io/serviceaccount/token
        relabel_configs:
        - source_labels: [__meta_kubernetes_namespace, __meta_kubernetes_service_name, __meta_kubernetes_endpoint_port_name]
          separator: ;
          regex: default;kubernetes;https
          replacement: ${1}
          target_label: namespace
        - source_labels: [__meta_kubernetes_namespace, __meta_kubernetes_service_name, __meta_kubernetes_endpoint_port_name]
          separator: ;
          regex: default;kubernetes;https
          replacement: ${2}
          target_label: service
        - source_labels: [__meta_kubernetes_namespace, __meta_kubernetes_service_name, __meta_kubernetes_endpoint_port_name]
          separator: ;
          regex: default;kubernetes;https
          replacement: ${3}
          target_label: port

This ConfigMap defines a prometheus.yml file that specifies how Prometheus should scrape metrics from Kubernetes API servers.

Create a StatefulSet

The next step is to create a StatefulSet that will manage the Prometheus deployment. This YAML file will create a StatefulSet with three replicas:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: prometheus
spec:
  selector:
    matchLabels:
      app: prometheus
  serviceName: prometheus
  replicas: 3
  template:
    metadata:
      labels:
        app: prometheus
    spec:
      containers:
      - name: prometheus
        image: prom/prometheus:v2.28.0
        args:
        - "--config.file=/etc/prometheus/prometheus.yml"
        ports:
        - containerPort: 9090
          name: http
        volumeMounts:
        - name: prometheus-data
          mountPath: /prometheus
        - name: prometheus-config
          mountPath: /etc/prometheus/prometheus.yml
      volumes:
      - name: prometheus-data
        persistentVolumeClaim:
          claimName: prometheus-data
      - name: prometheus-config
        configMap:
          name: prometheus-config
  volumeClaimTemplates:
  - metadata:
      name: prometheus-data
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 10Gi

This StatefulSet defines a prometheus container that uses the prom/prometheus:v2.28.0 image and mounts the prometheus-data PVC and the prometheus-config

References

1. Prometheus official website: https://prometheus.io/

2. Prometheus documentation: https://prometheus.io/docs/introduction/overview/

3. Prometheus GitHub repository: https://github.com/prometheus/prometheus

4. CNCF Prometheus project page: https://www.cncf.io/projects/prometheus/

5. Prometheus blog: https://blog.prometheus.io/

6. Prometheus community page: https://prometheus.io/community/

7. Grafana integration with Prometheus: https://grafana.com/docs/grafana/latest/features/datasources/prometheus/

8. Alertmanager documentation: https://prometheus.io/docs/alerting/alertmanager/

9. Kubernetes monitoring with Prometheus: https://kubernetes.io/docs/tasks/debug-application-cluster/resource-usage-monitoring/

10. Prometheus exporters: https://prometheus.io/docs/instrumenting/exporters/

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