Configuring scale to zero

    Scale to zero can only be enabled if you are using the KnativePodAutoscaler (KPA), and can only be configured globally. For more information about using KPA or global configuration, see the documentation on Supported Autoscaler types.

    The scale to zero value controls whether Knative allows replicas to scale down to zero (if set to ), or stop at 1 replica if set to false.

    Note

    For more information about scale bounds configuration per Revision, see the documentation on Configuring scale bounds.

    • Global key: enable-scale-to-zero
    • Per-revision annotation key: No per-revision setting.
    • Possible values: boolean
    • Default: true

    Global (ConfigMap)Global (Operator)

    1. apiVersion: operator.knative.dev/v1alpha1
    2. kind: KnativeServing
    3. metadata:
    4.   name: knative-serving
    5. spec:
    6.     autoscaler:

    This setting specifies an upper bound time limit that the system will wait internally for scale-from-zero machinery to be in place before the last replica is removed.

    Warning

    This is a value that controls how long internal network programming is allowed to take, and should only be adjusted if you experience issues with requests being dropped while a Revision is scaling to zero Replicas.

    • Global key: scale-to-zero-grace-period
    • Per-revision annotation key: n/a
    • Possible values: Duration
    • Default: 30s

    Example:

    Global (ConfigMap)Global (Operator)

    1. apiVersion: operator.knative.dev/v1alpha1
    2. kind: KnativeServing
    3. metadata:
    4.   name: knative-serving
    5. spec:
    6.   config:
    7.       scale-to-zero-grace-period: "40s"

    The flag determines the minimum amount of time that the last pod will remain active after the Autoscaler decides to scale pods to zero.

    This contrasts with the scale-to-zero-grace-period flag, which determines the maximum amount of time that the last pod will remain active after the Autoscaler decides to scale pods to zero.

    • Global key: scale-to-zero-pod-retention-period
    • Per-revision annotation key: autoscaling.knative.dev/scale-to-zero-pod-retention-period
    • Possible values: Non-negative duration string
    • Default: 0s

    Per RevisionGlobal (ConfigMap)Global (Operator)

    1. apiVersion: v1
    2. kind: ConfigMap
    3. metadata:
    4.  name: config-autoscaler
    5.  namespace: knative-serving
    6. data: