kubernetes/docs/user-guide/horizontal-pod-autoscaling/hpa-php-apache.yaml

apiVersion: extensions/v1beta1
kind: HorizontalPodAutoscaler
metadata:
  name: php-apache
  namespace: default
spec:
  scaleRef:
    kind: ReplicationController
    name: php-apache
    namespace: default
  minReplicas: 1
  maxReplicas: 10
  cpuUtilization:
    targetPercentage: 50