如何让k8s cpu和memory HPA协同工作？

Question

I'm using a k8s HPA template for CPU and memory like below:

---
apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: {{.Chart.Name}}-cpu
  labels:
    app: {{.Chart.Name}}
    chart: {{.Chart.Name}}
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: {{.Chart.Name}}
  minReplicas: {{.Values.hpa.min}}
  maxReplicas: {{.Values.hpa.max}}
  targetCPUUtilizationPercentage: {{.Values.hpa.cpu}}
---
apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: {{.Chart.Name}}-mem
  labels:
    app: {{.Chart.Name}}
    chart: {{.Chart.Name}}
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: {{.Chart.Name}}
  minReplicas: {{.Values.hpa.min}}
  maxReplicas: {{.Values.hpa.max}}
  metrics:
    - type: Resource
      resource:
        name: memory
        target:
          type: Utilization
          averageValue: {{.Values.hpa.mem}}

Having two different HPA is causing any new pods spun up for triggering memory HPA limit to be immediately terminated by CPU HPA as the pods' CPU usage is below the scale down trigger for CPU. It always terminates the newest pod spun up, which keeps the older pods around and triggers the memory HPA again, causing an infinite loop. Is there a way to instruct CPU HPA to terminate pods with higher usage rather than nascent pods every time?

Answer 1

As per the suggestion in comments, using a single HPA solved my issue. I just had to move CPU HPA to same apiVersion as memory HPA.

Answer 2

Autoscaling based on multiple metrics/Custom metrics:-

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: nginx
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: nginx
  minReplicas: 1
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 50
  - type: Resource
    resource:
      name: memory
      target:
        type: AverageValue
        averageValue: 100Mi

When created, the Horizontal Pod Autoscaler monitors the nginx Deployment for average CPU utilization, average memory utilization, and (if you uncommented it) the custom packets_per_second metric. The Horizontal Pod Autoscaler autoscales the Deployment based on the metric whose value would create the larger autoscale event.

https://cloud.google.com/kubernetes-engine/docs/how-to/horizontal-pod-autoscaling#kubectl-apply