Bootstrap Flux v2 with GitHub Repository

# Verify Flux CLI is installed
flux version

# Verify cluster meets Flux requirements
flux check --pre
# All checks should pass before proceeding

# Set environment variables
export GITHUB_TOKEN=ghp_yourpersonalaccesstoken
export GITHUB_USER=yourgithubusername
export GITHUB_REPO=flux-gitops-demo

# Bootstrap Flux — this command is idempotent and safe to re-run
flux bootstrap github \
  --owner=$GITHUB_USER \
  --repository=$GITHUB_REPO \
  --branch=main \
  --path=clusters/my-cluster \
  --personal \
  --private=false

# Watch Flux controllers start
kubectl get pods -n flux-system -w

# Expected pods:
# helm-controller-*         Running
# kustomize-controller-*    Running
# notification-controller-* Running
# source-controller-*       Running

# Verify Flux installed correctly
flux check

# Clone the repo that Flux bootstrapped
git clone https://github.com/$GITHUB_USER/$GITHUB_REPO
cd $GITHUB_REPO

# Create directory structure for the sample app
mkdir -p apps/base/nginx
mkdir -p apps/staging

# Create the base Deployment
cat > apps/base/nginx/deployment.yaml << 'EOF'
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-demo
  namespace: default
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx-demo
  template:
    metadata:
      labels:
        app: nginx-demo
    spec:
      containers:
      - name: nginx
        image: nginx:1.25.3    # pinned tag
        ports:
        - containerPort: 80
        resources:
          requests: {cpu: 50m, memory: 64Mi}
          limits: {cpu: 200m, memory: 128Mi}
EOF

# Create kustomization.yaml for the base
cat > apps/base/nginx/kustomization.yaml << 'EOF'
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- deployment.yaml
EOF

# Create Flux Kustomization resource
cat > clusters/my-cluster/nginx-app.yaml << 'EOF'
apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
  name: nginx-app
  namespace: flux-system
spec:
  interval: 1m0s         # Reconcile every minute
  path: ./apps/base/nginx
  prune: true            # Delete resources removed from Git
  sourceRef:
    kind: GitRepository
    name: flux-system    # Points to the repo Flux bootstrapped
  targetNamespace: default
  healthChecks:
  - apiVersion: apps/v1
    kind: Deployment
    name: nginx-demo
    namespace: default
EOF

# Commit and push to trigger Flux
git add -A
git commit -m "feat: add nginx demo application"
git push origin main

# Watch Flux reconcile (the GitOps loop)
flux get kustomizations --watch

# Expected output progression:
# NAME        READY   MESSAGE
# flux-system True    Applied revision: main@sha1:abc123
# nginx-app   False   Reconciliation in progress
# nginx-app   True    Applied revision: main@sha1:abc123

# Verify the deployment was created
kubectl get deployment nginx-demo
kubectl get pods -l app=nginx-demo

# Force immediate reconciliation (don't wait for interval)
flux reconcile kustomization nginx-app --with-source

# Change replicas from 2 to 3 in Git
sed -i 's/replicas: 2/replicas: 3/' apps/base/nginx/deployment.yaml

git add -A
git commit -m "scale: increase nginx replicas to 3"
git push origin main

# Watch Flux detect and apply the change
flux get kustomizations --watch

# In another terminal, watch the deployment scale
kubectl get deployment nginx-demo -w

# Verify final state matches Git
kubectl get deployment nginx-demo \
  -o jsonpath='{.spec.replicas}'
# Expected: 3

# View the full GitOps event history
flux events --for Kustomization/nginx-app

# Remove the deployment from Git
rm apps/base/nginx/deployment.yaml
# Update kustomization.yaml to remove the reference
cat > apps/base/nginx/kustomization.yaml << 'EOF'
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources: []
EOF

git add -A
git commit -m "test: remove nginx deployment (prune test)"
git push

flux reconcile kustomization nginx-app --with-source
kubectl get deployment nginx-demo
# Expected: Error from server (NotFound)
# Flux pruned the resource because it was removed from Git

# Restore the deployment
git revert HEAD --no-edit
git push
flux reconcile kustomization nginx-app --with-source