Scale-to-zero - Autoscaling | Serving | Red Hat OpenShift Serverless 1.34

Enabling scale-to-zero
Configuring the scale-to-zero grace period

Knative Serving provides automatic scaling, or autoscaling, for applications to match incoming demand.

Enabling scale-to-zero

You can use the enable-scale-to-zero spec to enable or disable scale-to-zero globally for applications on the cluster.

Prerequisites

You have installed OpenShift Serverless Operator and Knative Serving on your cluster.
You have cluster administrator permissions on OpenShift Container Platform, or you have cluster or dedicated administrator permissions on Red Hat OpenShift Service on AWS or OpenShift Dedicated.
You are using the default Knative Pod Autoscaler. The scale to zero feature is not available if you are using the Kubernetes Horizontal Pod Autoscaler.

Procedure

Modify the enable-scale-to-zero spec in the KnativeServing custom resource (CR):

Example KnativeServing CR

apiVersion: operator.knative.dev/v1beta1
kind: KnativeServing
metadata:
  name: knative-serving
spec:
  config:
    autoscaler:
      enable-scale-to-zero: "false" (1)

1	The `enable-scale-to-zero` spec can be either `"true"` or `"false"`. If set to true, scale-to-zero is enabled. If set to false, applications are scaled down to the configured minimum scale bound. The default value is `"true"`.

Configuring the scale-to-zero grace period

Knative Serving provides automatic scaling down to zero pods for applications. You can use the scale-to-zero-grace-period spec to define an upper bound time limit that Knative waits for scale-to-zero machinery to be in place before the last replica of an application is removed.

Prerequisites

You have installed OpenShift Serverless Operator and Knative Serving on your cluster.
You have cluster administrator permissions on OpenShift Container Platform, or you have cluster or dedicated administrator permissions on Red Hat OpenShift Service on AWS or OpenShift Dedicated.
You are using the default Knative Pod Autoscaler. The scale-to-zero feature is not available if you are using the Kubernetes Horizontal Pod Autoscaler.

Procedure

Modify the scale-to-zero-grace-period spec in the KnativeServing custom resource (CR):

Example KnativeServing CR

apiVersion: operator.knative.dev/v1beta1
kind: KnativeServing
metadata:
  name: knative-serving
spec:
  config:
    autoscaler:
      scale-to-zero-grace-period: "30s" (1)

1	The grace period time in seconds. The default value is 30 seconds.