monitoring_an_application_with_prometheus.md

Monitoring an application with prometheus

I configured a web application with prometheus to monitor its:

• version
• http_requests_total
• http_request_duration_seconds
• http_request_duration_seconds_count
• http_request_duration_seconds_sum

Used Technologies:

• AWS
• Kubernete
• Docker
• Prometheus & Grafana (Monitoring)

How I built this project:

• First of all, A web application was prepared to host all of the metrics data at endpoint /metrics with the help of prometheus library so that the configured prometheus can scrape metrics data from the web application endpoint metrics at an interval.

• Then, A Container image was built of the application, That can be found here.

• Then I deployed a deployment resource in my running Kubernetes cluster on AWS EKS:

  apiVersion: apps/v1
  kind: Deployment
  metadata:
    labels:
      app.kubernetes.io/name: prometheus-example-app
    name: prometheus-example-app
  spec:
    replicas: 1
    selector:
      matchLabels:
        app.kubernetes.io/name: prometheus-example-app
    template:
      metadata:
        labels:
          app.kubernetes.io/name: prometheus-example-app
      spec:
        containers:
        - name: prometheus-example-app
          image: mdsahiloss/prometheus-example-app:latest
          ports:
          - name: web
            containerPort: 8080
  

• And then, I Created a ClusterIP service inside K8s, So that other resources in K8s can communicate with the application pods.

• And then, I installed a promentheus operator in my running Kubernetes cluster on AWS EKS, By following the instructions available here.

• And then created a resource ServiceMonitor (CRD of this resource is provided by the installed Prometheus-Operator) inside K8s cluster in default namespace:

   apiVersion: monitoring.coreos.com/v1
   kind: ServiceMonitor
   metadata:
     labels:
       app.kubernetes.io/name: prometheus-example-app-svc-monitor
     name: prometheus-example-app-svc-monitor
   spec:
     selector:
       matchLabels:
         app.kubernetes.io/name: prometheus-example-app-svc
     endpoints:
       - port: http
     namespaceSelector:
       any: true
  

That's it after this, I was able to see all the metrics generated by my application on the prometheus web which is runnning in my K8s Cluster.