Setting replicas for K8s deployment leveraging ytt

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: spring-on-k8s
spec:
  replicas: 1
  selector:
    matchLabels:
      app: spring-on-k8s
  template:
    metadata:
      labels:
        app: spring-on-k8s
    spec:
      containers:
      - image: ghcr.io/alexandreroman/spring-on-k8s
        name: app
        resources:
          limits:
            memory: 1Gi
        ports:
        - containerPort: 8080
        livenessProbe:
          httpGet:
            port: 8080
            path: /actuator/health/liveness
        readinessProbe:
          httpGet:
            port: 8080
            path: /actuator/health/readiness

overlay-deployment.yaml

#@ load("@ytt:overlay", "overlay")
#@overlay/match by=overlay.subset({"metadata":{"name":"spring-on-k8s"}, "kind": "Deployment"}), expects=1
---
spec:
  replicas: 3