GKE GitOps + Observability Lab

This repository demonstrates a practical GitOps-based Kubernetes deployment on Google Kubernetes Engine (GKE), combined with full observability using Prometheus and Grafana.

It represents a clean, production-style setup using industry-standard tools and workflows.

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🛠 Technologies Used

• Google Kubernetes Engine (GKE)
• Terraform
• Helm
• Argo CD (GitOps)
• Prometheus
• Grafana
• NGINX Sample API
• GitHub (GitOps repository)

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🏗 Architecture Overview

GitHub (main branch)
│
▼
Argo CD
│
▼
GKE Cluster (asia-northeast1-b)
│
├── sample-api (NGINX)
└── Monitoring (Prometheus + Grafana)

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📂 Repository Structure

gke-gitops-observability-lab/
│
├── terraform/                   # Terraform code to provision VPC + GKE
│
├── apps/
│   └── sample-api/               # Helm chart for NGINX application
│
├── argocd/
│   └── sample-api-app.yaml       # Argo CD Application manifest
│
├── docs/
│   └── screenshots/              # Grafana / Argo / Architecture screenshots
│
└── README.md

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🚀 Deployment Flow

1️⃣ Infrastructure Provisioning (Terraform)

cd terraform
terraform init
terraform plan
terraform apply

This creates:

• VPC + Subnet
• GKE Cluster in asia-northeast1-b
• Required IAM / networking components

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2️⃣ Monitoring Stack Installation (Helm)

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

helm install prometheus prometheus-community/kube-prometheus-stack \
  --namespace monitoring --create-namespace

Verify:

kubectl get pods -n monitoring

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3️⃣ Sample Application Deployment (Helm)

kubectl create namespace apps

cd apps/sample-api
helm install sample-api . -n apps

Verify:

kubectl get pods -n apps
kubectl get svc -n apps

You should see an external IP attached to the sample-api service.

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🔄 GitOps Deployment (Argo CD)

Apply the Argo CD application

kubectl apply -n argocd -f argocd/sample-api-app.yaml

Argo CD will now:

• Monitor this GitHub repository
• Compare desired state vs actual state
• Automatically sync Kubernetes resources

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🌐 Argo CD Web UI Access

Start port-forwarding

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

Then open in browser:

http://localhost:8080

Login details

Default username:

admin

Get the initial password:

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

After login, you should see:

• ✅ Application: sample-api
• ✅ Status: Synced
• ✅ Health: Healthy
• ✅ Source: GitHub repository
• ✅ Target: apps namespace in GKE

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📊 Grafana Web UI Access (Observability)

Start port-forwarding

kubectl port-forward -n monitoring svc/prometheus-grafana 3000:80

Open in browser:

http://localhost:3000

Username:

admin

Get the password:

kubectl get secret --namespace monitoring prometheus-grafana \
  -o jsonpath="{.data.admin-password}" | base64 --decode ; echo

Available dashboards:

• Kubernetes / Cluster
• Pods / Nodes / Workloads
• CoreDNS & Networking
• etcd, kubelet, API server

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✅ How to Validate GitOps is Working

1. Edit this file in GitHub:

apps/sample-api/values.yaml

Example change:

replicaCount: 3

2. Commit & Push to GitHub

git add apps/sample-api/values.yaml
git commit -m "Increase replicas to 3"
git push

3. In Argo CD Web UI:

• Click Refresh
• Then Sync

4. Verify:

kubectl get pods -n apps

✅ You should now see 3 pods running

This confirms:

• GitHub → Argo CD → GKE is fully working ✅

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✅ Key Features

• Real GitOps workflow using Argo CD
• Infrastructure as Code with Terraform
• Helm-based application deployment
• Full observability (Prometheus + Grafana)
• Reproducible & scalable architecture
• Production-style structure

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This repository is intended as a reference, learning resource, and example of best practices for GitOps-based Kubernetes operations on GCP.