Kubernetes Monitoring: Prometheus, Grafana, ArgoCD

In the last blog, I configured an ArgoCD-based GitOps pipeline and deployed my distributed app called vote-app. In this post, I’ll walk through how to set up Prometheus and Grafana to monitor the Kubernetes cluster and track resource usage of the vote-app pods, such as memory and CPU.

This setup assumes you already have a Kubernetes cluster and ArgoCD installed. If not, check the installation section of my previous blog.

Outline

What is Observability
Prometheus and Grafana
kube-prometheus-stack
Setting up kube-prometheus-stack

Prerequisites

Kubernetes Cluster
ArgoCD (see my previous blog for setup instructions)

Observability

Observability is the ability to understand the internal state of a system by examining the data it produces—logs, metrics, and traces. Highly observable systems make it easier to detect and diagnose complex issues.

It's not just about bugs and outages but also about understanding the impact of changes in your code.

Three Pillars of Observability

Logs: Time-stamped records of events that are often unstructured and verbose.
Traces: Visualize the lifecycle of a request across services. Useful for understanding latency and bottlenecks, especially in distributed systems.
Metrics: Numeric data that represent the behavior of your system (e.g., CPU usage, request count).

For this blog, we’ll focus on the metrics pillar.

Prometheus and Grafana

Prometheus

Prometheus is a CNCF-hosted monitoring and alerting toolkit. It scrapes metrics using a pull-based approach and stores them in a time-series database. It supports dynamic target discovery via Kubernetes service discovery.

Grafana

Grafana is an open-source observability platform. Although Prometheus provides a UI for querying metrics, Grafana makes it easier to visualize those metrics using beautiful dashboards.

kube-prometheus-stack

We’ll use the kube-prometheus-stack Helm chart, which bundles all components required for Kubernetes monitoring:

Prometheus: Scrapes, stores, and exposes metrics.
Node Exporter: Collects node-level metrics. And Prometheus scrapes data prepared by this exporter.
Kube-State-Metrics: This one is another exporter. Exposes information about Kubernetes objects, such as Pods and containers.
Grafana: Dashboards and visualizations.
Alertmanager: Sends notifications based on alerts.

For more details, check this Spacelift tutorial.

Setup kube-prometheus-stack

In ArgoCD UI, go to Applications → New App → Edit as YAML.
Paste the following YAML:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: 'kube-prometheus-stack'
spec:
  project: default
  source:
    repoURL: https://prometheus-community.github.io/helm-charts
    targetRevision: 73.2.0
    helm:
      values: |
        grafana:
          service:
            type: NodePort
            nodePort: 31006
        prometheus:
          service:
            type: NodePort
            nodePort: 31005
    chart: kube-prometheus-stack
  destination:
    server: <https://kubernetes.default.svc>
    namespace: kube-prometheus-stack
  syncPolicy:
    syncOptions:
      - CreateNamespace=true
    automated:
      prune: false
      selfHeal: false

I’ve changed the default ClusterIP services to NodePort so we can access Prometheus and Grafana from the browser.

Click Save, then Create.

ArgoCD create app

After creation, the stack will appear in your ArgoCD dashboard:

ArgoCD dashboard

Try Prometheus

Access Prometheus at http://YOUR_NODE_IP:31005/

Type a query in the Enter expression field you can type queries in PromQL syntax. E.g. typing node_memory_Active_bytes to see memory utilization.

Click Execute to view memory usage per node. Use the Table tab for raw data and the Graph tab for visualization.

Prometheus UI

Visualize Metrics Using Grafana

Access Grafana at http://YOUR_NODE_IP:31006/

Username: admin
Password: prom-operator

After logging in, you see this Grafana welcome page:

Grafana Welcome

Click Dashboards in the sidebar. Explore pre-built dashboards such as:

Kubernetes / Compute Resources / Cluster – Overview of your cluster’s resource usage.

Cluster Dashboard

Kubernetes / Compute Resources / Namespace (Pods) – View resource usage by namespace. Select vote-app from the dropdown to see pod-specific metrics. By doing this I can see how my vote-app utilizing resources in this Kubernetes cluster.

vote-app Dashboard

Recap

In this post, we set up the popular Prometheus and Grafana monitoring stack in our Kubernetes cluster using only the ArgoCD GUI—no CLI required. We explored how to view resource metrics like memory, CPU, and network usage for our vote-app via Grafana dashboards.

To further analyze our application, we could implement custom application metrics (e.g., total votes, requests/sec) in vote-app by creating exporters, and configure Prometheus to scrape them.

Monitoring Kubernetes Cluster with Prometheus and Grafana using ArgoCD