Kubernetes - when to use HorizontalPodAutoscaler resource type?

Question

As mentioned in this answer: allow for easy updating of a Replica Set as well as the ability to roll back to a previous deployment.

So, kind: Deployment scales replicasets, which scales Pods, supports zero-downtime updates by creating and destroying replicasets

What is the purpose of HorizontalPodAutoscaler resource type?

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: xyz
spec:
  maxReplicas: 4
  minReplicas: 2
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: xyz
  targetCPUUtilizationPercentage: 70

score 1 · Accepted Answer · answered Oct 03 '21 at 15:20

1

As you write, with a Deployment it is easy to manually scale an app horizontally, by changing the numer of replicas.

By using a HorizontalPodAutoscaler, you can automate the horizontal scaling by e.g. configuring some metric thresholds, therefore the name autoscaler.

answered Oct 03 '21 at 15:20

Jonas

121,568
97
310
388

So, where has the automation happened for scaling? in the given template – overexchange Oct 03 '21 at 15:29
the HPA will update the replicas in your Deployment – Jonas Oct 03 '21 at 15:31
ok, so without changing the existing deployment, HPA change the replicaset property of running deployment. – overexchange Oct 03 '21 at 15:34
It changes the `replicas:` field in the Deployment object. – David Maze Oct 03 '21 at 21:09

Kubernetes - when to use HorizontalPodAutoscaler resource type?

1 Answers1