Kubernetes HPA change polling interval

I use Horizontal Pod Autoscaler with External metric based on a value provided by DataDog agent

apiVersion: datadoghq.com/v1alpha1
kind: DatadogMetric
metadata:
  name: queue-size
spec:
  query: "max:redis.key.length{key:my-tasks}.fill(zero)"

Corresponding HPA configuration

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: celery-worker
  metrics:
  - type: External
    external:
      metric:
        name: "datadogmetric@default:queue-size"

I want workers to be scaled almost immediately as queue grows, so need polling period to be at most 2-5 seconds. By default it's 30 seconds (as per docs)

How do I change poll interval on k8s side? Is there a flag when configuring HPA or should I tune DataDog agent instead?

Solution 1:

Kubernetes implements horizontal pod autoscaling as a control loop that runs intermittently (it is not a continuous process). The interval is set by the --horizontal-pod-autoscaler-sync-period parameter to the kube-controller-manager (and the default interval is 15 seconds). You should tweak the value as per your requirement