Kubernetes horizontal pod autoscaling initial delay?

Question

Is there a configuration in Kubernetes horizontal pod autoscaling to specify a minimum delay for a pod to be running or created before scaling up/down?

For example with something like:

# I am looking for a flag like this
--horizontal-pod-autoscale-initial-upscale-delay=5m0s

# Similar to these existing flags
--horizontal-pod-autoscaler-downscale-delay=2m0s
--horizontal-pod-autoscaler-upscale-delay=2m0s

Having as a result:

• Wait for 5 min before any upscale occur
• After 5 min, perform a downscale at most every 2 min

I have a situation where a Pod consumes lots of resources on start-up for bootstrapping (which is expected) but I don't want it scaled during this time, and once bootstrap is done it may be eligible for autoscaling.

Detumescence

Answer 1

This flag actually exists: --horizontal-pod-autoscaler-cpu-initialization-period In addition you need to consider the readiness delay: --horizontal-pod-autoscaler-initial-readiness-delay and the metric loop time, --horizontal-pod-autoscaler-sync-period to calculate the total (max/min/average) delay.

See https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/

Biak

Thanks, I missed that one. Formulation is quite confusing though. Issue github.com/kubernetes/website/issues/12657 is pointing at that – Detumescence

@Biak How to define it in yaml? – Excessive

In addition to the comment from @RonakPatel, do you know where the flags should be provided in CLI? kubectl autoscale doesn't seem to accept them. – Jeraldinejeralee

These flags are applied globally to the cluster and cannot be configured per HPA object. If you're using a hosted Kubernetes solution, they are most likely configured by the provider. – Prosector

Sadly enough neither of those two parameters (horizontal-pod-autoscaler-cpu-initialization-period, horizontal-pod-autoscaler-initial-readiness-delay) are available in OpenShift 3.11 – Countermark

If you are using CPA-HPA instead of standard HPA, the equivalent command as YAML for initial readiness is initialReadinessDelay - horizontal-pod-autoscaler.readthedocs.io/en/latest/user-guide/… But, again, this is not for standard HPA. CPA-HPA is almost a drop-in replacement for HPA. – Moderation