Kubernetes Exercise: Deploy a Sample Application Using Argo CD (GitOps)

Objectives

By the end of this exercise, you will:

1. Install Argo CD on a Kubernetes cluster.
2. Deploy a sample application from a GitHub repository using Argo CD.
3. Access and verify the deployed application.

Prerequisites

• A running Kubernetes cluster (Minikube, kind, or cloud-based)
• kubectl installed and configured
• argocd CLI installed (brew install argocd or via https://argo-cd.readthedocs.io/en/stable/cli_installation/)
• Access to GitHub (optional: your own repo)

Step 1: Install Argo CD

kubectl create namespace argocd

kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

Wait for the pods to become ready:

kubectl get pods -n argocd

Step 2: Access the Argo CD UI

Option 1: Port-forward the Argo CD API server

kubectl port-forward svc/argocd-server -n argocd 8080:443

Now access it via: https://localhost:8080

Step 3: Login to Argo CD

Get the initial admin password:

kubectl get secret argocd-initial-admin-secret -n argocd -o jsonpath="{.data.password}" | base64 -d && echo

Then log in via CLI:

argocd login localhost:8080 --username admin --password <copied-password> --insecure

Step 4: Deploy a Sample Application

We'll use a public GitHub repo with a simple nginx deployment:

Repo: https://github.com/argoproj/argocd-example-apps.git Path: guestbook

Create a new namespace for the app

kubectl create namespace guestbook

Create an Argo CD Application manifest (guestbook-app.yaml)

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: guestbook
  namespace: argocd
spec:
  destination:
    namespace: guestbook
    server: https://kubernetes.default.svc
  project: default
  source:
    repoURL: https://github.com/argoproj/argocd-example-apps.git
    targetRevision: HEAD
    path: guestbook
  syncPolicy:
    automated:
      prune: true
      selfHeal: true

Apply it:

kubectl apply -f guestbook-app.yaml

Step 5: Verify the Deployment

Check the application in Argo CD UI or via CLI:

argocd app list
argocd app get guestbook

Make sure the sync status is Synced and health is Healthy.

Step 6: Access the Application

Port-forward the frontend service:

kubectl port-forward svc/guestbook-ui -n guestbook 8081:80

Visit: http://localhost:8081

You should see the Guestbook UI running!