add HPA to Kubernetes deployment

kustomize/app/deployment.yaml

@@ -6,7 +6,6 @@ metadata:
   annotations:
     reloader.stakater.com/auto: "true"
 spec:
-  replicas: 5
   selector:
     matchLabels:
       app: kubernaut

kustomize/app/hpa.yaml

@@ -0,0 +1,19 @@
+---
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: kubernaut
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: kubernaut
+  minReplicas: 1
+  maxReplicas: 10
+  metrics:
+  - type: Resource
+    resource:
+      name: cpu
+      target:
+        type: Utilization
+        averageUtilization: 50

kustomize/app/kustomization.yaml

@@ -6,4 +6,5 @@ resources:
   - secret.yaml
   - configmap.yaml
   - deployment.yaml
+  - hpa.yaml
   - services.yaml