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Panchanan Panigrahi
Panchanan Panigrahi

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Real-world Prometheus Deployment: A Practical Guide for Kubernetes Monitoring

#prometheus #sitereliabilityengineering #devops #beginners

Aim Of This Project:

The primary goal of this Prometheus Lab project is to provide hands-on experience and guidance in setting up a Prometheus monitoring system on a Kubernetes cluster. By following the step-by-step instructions and understanding the associated Kubernetes resources, participants will gain practical insights into deploying Prometheus for efficient system observability.

Project architecture:

Project architecture:

Prerequisites

  1. To install k3d, you can use the following command:

    curl -s https://raw.githubusercontent.com/rancher/k3d/main/install.sh | bash

  2. Check out my GitHub Repo:

    https://github.com/panchanandevops/Learning-Prometheus.git

  3. **Create a Namespace for Monitoring:

    kubectl create namespace monitoring

  4. Add Helm Repository:

    helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm repo update

  5. Store Default values.yaml

    helm show values prometheus-community/kube-prometheus-stack > values.yaml

  6. Install kube-prometheus-stack Helm Chart in monitoring Namespace:

    helm install prometheus-stack prometheus-community/kube-prometheus-stack -n monitoring

  7. Verify Deployment, after some time:

    kubectl get pods -n monitoring

Access Prometheus Dashboard:
run the following command to access the Prometheus UI

    kubectl port-forward svc/prometheus-stack-prometheus -n monitoring 9090:9090
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  • Open your web browser and navigate to http://localhost:9090 to access the Prometheus dashboard.

Prometheus dashboard

Access Grafana Dashboard:
run the following command to access the Grafana UI

    kubectl port-forward svc/prometheus-stack-grafana -n monitoring 8080:80
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  • Open your web browser and navigate to http://localhost:8080.

Grafana Dashboard

Login with the default credentials:
Username: admin. Retrieve the password using the following command:

    kubectl get secret prometheus-stack-grafana -n monitoring -o jsonpath='{.data.admin-password}' | base64 --decode ; echo
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Change in values.yaml

In order to select AltermanagerConfig, we need to change our values.yaml file.

Search in values.yaml for alertmanagerConfigSelector

then replace that section with the following section

altermanagerConfigSelector:
    matchLabels:
    release: prometheus
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Apply our k8s-yaml resources:

run the following command to deploy all resources with crds in k8s.

kubectl apply -f <your-path>/k8s-yaml/
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Lets Understand All Kubernetes resources:

Deployment

Let's break down the Kubernetes Deployment YAML file in a clear and simple way:

API Version and Kind: 

apiVersion: apps/v1
kind: Deployment
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This part specifies the API version (apps/v1) and the type of Kubernetes resource (Deployment) we're defining.

Metadata: 

metadata:
  name: my-deployment
  labels:
    app: api
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In this part, we provide metadata for our Deployment. The name is set to my-deployment, and it carries a label (app: api) for identification.

Specification (spec):

Selector: 

selector:
  matchLabels:
    app: api
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Here, we define a selector with labels. Pods controlled by this Deployment will have labels matching app: api.

Template: 

template:
  metadata:
    labels:
      app: api
  spec:
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In the template, we describe the pods created by our Deployment. Metadata labels are set, ensuring they match the selector labels.

Pod Specification (spec inside the template): 

    containers:
      - name: mycontainer
        image: panchanandevops/myexpress:v0.1.0
        resources:
          limits:
            memory: "128Mi"


            cpu: "500m"
        ports:
          - containerPort: 3000
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Within the pod, we define a container named mycontainer. It uses the Docker image panchanandevops/myexpress:v0.1.0, has resource limits for memory and CPU, and exposes port 3000.

Service

Let's break down the Kubernetes Service YAML file in a clear and simple way:

API Version and Kind: 

apiVersion: v1
kind: Service
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This section specifies the API version (v1) and the type of Kubernetes resource (Service) we're defining.

Metadata: 

metadata:
  name: my-service
  labels:
    job: node-api
    app: api
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Here, we provide metadata for our Service. The name is set to my-service, and it carries labels for identifying the associated job (node-api) and application type (api).

Specification (spec): 

spec:
  type: ClusterIP
  selector:
    app: api
  ports:
    - name: web
      protocol: TCP
      port: 3000
      targetPort: 3000
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In this part, we define the specifications for our Service:

  • type: ClusterIP: Specifies that the Service is of type ClusterIP.
  • selector: Used to match pods for this service, and in this case, it selects pods with the label app: api.
  • ports: Defines a port named web with TCP protocol, available on port 3000, targeting the pods on their port 3000.

ServiceMonitor

Let's break down the Kubernetes ServiceMonitor YAML file in a clear and simple way:

API Version and Kind: 

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
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This section specifies the API version (monitoring.coreos.com/v1) and the type of Kubernetes resource (ServiceMonitor) we're defining.

Metadata: 

metadata:
  name: api-service-monitor
  labels:
    release: prometheus
    app: prometheus
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Here, we provide metadata for our ServiceMonitor. The name is set to api-service-monitor, and it carries labels for release association (release: prometheus) and identifying the application type (app: prometheus).

Specification (spec): 

spec:
  jobLabel: job
  selector:
    matchLabels:
      app: api
  endpoints:
    - port: web
      path: /swagger-stats/metrics
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In this part, we define the specifications for our ServiceMonitor:

  • jobLabel: job: Specifies the label (job) used to identify the job for Prometheus.
  • selector: Used to match pods for monitoring; it selects pods with the label app: api.
  • endpoints: Defines the endpoints to scrape metrics. In this case, it specifies a port named web and the path /swagger-stats/metrics to fetch metrics from.

PrometheusRules

Let's break down the Kubernetes PrometheusRules YAML file in a clear and simple way:

API Version and Kind: 

apiVersion: monitoring.coreos.com/v1
kind: PrometheusRule
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This section specifies the API version (monitoring.coreos.com/v1) and the type of Kubernetes resource (PrometheusRule) we're defining.

Metadata: 

metadata:
  name: api-prometheus-rule
  labels:
    release: prometheus
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Here, we provide metadata for our PrometheusRule. The name is set to api-prometheus-rule, and it carries labels for release association (release: prometheus).

Specification (spec): 

spec:
  groups:
    - name: api
      rules:
        - alert: down
          expr: up == 0
          for: 0m
          labels:
            severity: Critical
          annotations:
            summary: Prometheus target missing {{$labels.instance}}
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In this part, we define the specifications for our PrometheusRule:

  • groups: An array of rule groups. In this case, we have one group named api.
    • name: api: Name of the rule group.
    • rules: An array of rules within the group.
    • alert: down: Name of the alert.
    • expr: up == 0: Expression to trigger the alert when the metric 'up' is equal to 0.
    • for: 0m: Minimum duration for which the alert condition must be true to trigger the alert.
    • labels: Additional labels associated with the alert (e.g., severity).
    • annotations: Annotations provide additional information about the alert (e.g., summary).

Alertmanagerconfig

Let's break down the Kubernetes Alertmanagerconfig YAML file in a clear and simple way:

API Version and Kind: 

apiVersion: monitoring.coreos.com/v1
kind: AlertmanagerConfig
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This section specifies the API version (monitoring.coreos.com/v1) and the type of Kubernetes resource (AlertmanagerConfig) we're defining.

Metadata: 

metadata:
  name: alertmanager-config
  labels:
    release: prometheus
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Here, we provide metadata for our AlertmanagerConfig. The name is set to alertmanager-config, and it carries labels for release association (release: prometheus).

Specification (spec):

  1. Part 1: Route Configuration:

      spec:
    route:
      groupBy: ["severity"]
      groupWait: 30s
      groupInterval: 5m
      repeatInterval: 12h
      receiver: "team-notifications"

  2. Part 2: Receiver Configuration:

      spec:
    receivers:
      - name: "team-notifications"
        emailConfigs:
          - to: "team@example.com"
            sendResolved: true

  • - name: "team-notifications": Name of the receiver.

  • emailConfigs: Email-specific configuration.

  • - to: "team@example.com": Email address to which notifications are sent.

  • sendResolved: true: Indicates whether to send notifications when alerts are resolved.

Acknowledgment

Special thanks to my teacher Sir Sanjeev Thiyagarajan for his guidance, and to the KodeKloud YouTube channel for valuable insights into DevOps practices.

I extend my sincere gratitude to all the readers who have dedicated their valuable time and exhibited patience in exploring this content. Your commitment to learning and understanding is truly appreciated.

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