ops-demo/docs/02-deploy-podinfo.md

Exercise 02 — Deploy podinfo via GitOps

Time: ~30 min Goal: Deploy a real application to the cluster purely through Git — no kubectl apply.

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What you'll learn

• How adding an ArgoCD Application manifest to Git is the only deploy action needed
• How to read ArgoCD sync status and application health
• The GitOps feedback loop: commit → push → ArgoCD detects change → cluster updated

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Prerequisites

Exercise 01 complete: ArgoCD is running and the root app is Synced.

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Background: what is podinfo?

podinfo is a tiny Go web app by Stefan Prodan (ArgoCD's author) — often used in Kubernetes demos. It shows its own version number, has /healthz and /readyz endpoints, and looks good in a browser. No external dependencies, no secrets needed.

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Steps

1. Understand what already exists

The repo already contains the podinfo manifests. Take a look:

ls manifests/apps/podinfo/
# namespace.yaml  deployment.yaml  service.yaml

Open manifests/apps/podinfo/deployment.yaml and find the image tag:

image: ghcr.io/stefanprodan/podinfo:6.6.2

This is version 6.6.2. Remember it — you'll upgrade it later.

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2. Create the ArgoCD Application

This is the only thing you need to "deploy" the app — tell ArgoCD to watch the manifests:

cat apps/apps/podinfo.yaml

You'll see it points ArgoCD at manifests/apps/podinfo/ in this repo. The app already exists in the repo, so ArgoCD's root app will pick it up automatically.

Check ArgoCD now — you should already see a podinfo application appearing.

The GitOps point: You didn't run any kubectl apply for podinfo. You committed apps/apps/podinfo.yaml to Git, and ArgoCD synced it. That's the entire workflow.

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3. Watch it sync

kubectl get application podinfo -n argocd -w

Wait until you see Synced and Healthy. Then:

kubectl get pods -n podinfo
# NAME                       READY   STATUS    RESTARTS   AGE
# podinfo-xxxxxxxxx-xxxxx    1/1     Running   0          30s

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4. Verify the app is working

Port-forward to test locally (inside the VM):

kubectl port-forward svc/podinfo -n podinfo 9898:80

In another terminal (or using curl inside the VM):

curl http://localhost:9898
# {"hostname":"podinfo-xxx","version":"6.6.2", ...}

You can see "version":"6.6.2" — that matches the image tag in deployment.yaml.

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5. Make a GitOps change

Let's change the UI color to prove the loop works.

Edit manifests/apps/podinfo/deployment.yaml and change:

value: "#6C48C5"

to any hex color you like, e.g.:

value: "#2ecc71"

Commit and push:

git add manifests/apps/podinfo/deployment.yaml
git commit -m "chore: change podinfo UI color"
git push

Within ~3 minutes (ArgoCD's default poll interval) you'll see the pod restart and the new color appear. You can also click Refresh in the ArgoCD UI to trigger an immediate sync.

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Expected outcome

NAME      SYNC STATUS   HEALTH STATUS
podinfo   Synced        Healthy

curl http://localhost:9898 | jq .version
# "6.6.2"

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Troubleshooting

Symptom	Fix
Application stuck in "Progressing"	kubectl describe pod -n podinfo — usually image pull
ImagePullBackOff	Image was pre-pulled; run kubectl get events -n podinfo
ArgoCD shows OutOfSync after push	Click Refresh or wait 3 min for next poll

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What's next

podinfo is running but only accessible via port-forward. In Exercise 03 you'll expose it on your LAN using MetalLB (a real load balancer) and Ingress-Nginx, so you can reach it from your laptop's browser without any port-forward.