Kustomize Overlay Builder

# overlays/production/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

namespace: my-app-production

bases:
  - ../../base

commonLabels:
  app: my-app
  environment: production

replicas:
  - name: my-app
    count: 3

images:
  - name: my-app
    newName: my-registry/my-app
    newTag: "1.2.0"

patches:
  - path: patches/deployment-patch.yaml

# overlays/production/patches/deployment-patch.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  template:
    spec:
      containers:
        - name: my-app
          resources:
            requests:
              cpu: "500m"
              memory: "512Mi"
            limits:
              cpu: "2"
              memory: "1Gi"

# Apply: kubectl apply -k overlays/production