Metrics

The metric configuration defines which metric type is watched by the Autoscaler.

Setting metrics per revision

For per-revision configuration, this is determined using the autoscaling.knative.dev/metric annotation. The possible metric types that can be configured per revision depend on the type of Autoscaler implementation you are using:

  • The default KPA Autoscaler supports the concurrency and rps metrics.
  • The HPA Autoscaler supports the cpu metric.

For more information about KPA and HPA, see the documentation on Supported Autoscaler types.

  • Per-revision annotation key: autoscaling.knative.dev/metric
  • Possible values: "concurrency", "rps", "cpu", "memory" or any custom metric name, depending on your Autoscaler type. The "cpu", "memory", and "custom" metrics are only supported on revisions that use the HPA class.
  • Default: "concurrency"

Per-revision concurrency configurationPer-revision rps configurationPer-revision cpu configurationPer-revision memory configurationPer-revision custom metric configuration

  1. apiVersion: serving.knative.dev/v1
  2. kind: Service
  3. metadata:
  4.   name: helloworld-go
  5.   namespace: default
  6. spec:
  7.   template:
  8.     metadata:
  9.       annotations:
  10.         autoscaling.knative.dev/metric: "concurrency"
  1. apiVersion: serving.knative.dev/v1
  2. kind: Service
  3. metadata:
  4.   name: helloworld-go
  5.   namespace: default
  6. spec:
  7.   template:
  8.     metadata:
  9.       annotations:
  10.         autoscaling.knative.dev/metric: "rps"
  1. apiVersion: serving.knative.dev/v1
  2. kind: Service
  3. metadata:
  4.   name: helloworld-go
  5.   namespace: default
  6. spec:
  7.   template:
  8.     metadata:
  9.       annotations:
  10.         autoscaling.knative.dev/class: "hpa.autoscaling.knative.dev"
  11.         autoscaling.knative.dev/metric: "cpu"
  1. apiVersion: serving.knative.dev/v1
  2. kind: Service
  3. metadata:
  4.   name: helloworld-go
  5.   namespace: default
  6. spec:
  7.   template:
  8.     metadata:
  9.       annotations:
  10.         autoscaling.knative.dev/class: "hpa.autoscaling.knative.dev"
  11.         autoscaling.knative.dev/metric: "memory"

You can create an HPA to scale the revision by a metric that you specify. The HPA will be configured to use the average value of your metric over all the Pods of the revision.

  1. apiVersion: serving.knative.dev/v1
  2. kind: Service
  3. metadata:
  4.   name: helloworld-go
  5.   namespace: default
  6. spec:
  7.   template:
  8.     metadata:
  9.       annotations:
  10.         autoscaling.knative.dev/class: "hpa.autoscaling.knative.dev"
  11.         autoscaling.knative.dev/metric: "<metric-name>"

Where <metric-name> is your custom metric.

Next steps