Configure Scaling Metrics

Autoscaling metric configuration on an InterceptorRoute

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The scalingMetric field on an InterceptorRoute determines what metric drives autoscaling. You can scale based on concurrent request count, request rate, or both. At least one metric must be set.

Concurrency metric

Scale based on the number of in-flight requests per replica:

apiVersion: http.keda.sh/v1beta1
kind: InterceptorRoute
metadata:
  name: my-app
spec:
  target:
    service: <your-service>
    port: <your-port>
  scalingMetric:
    concurrency:
      targetValue: 100

The add-on targets targetValue concurrent requests per replica. When the total concurrent requests across all replicas exceeds replicas * targetValue, KEDA scales up.

Field	Required	Description
`targetValue`	Yes	Target concurrent request count per replica.

Request rate metric

Scale based on requests per second, averaged over a sliding window:

apiVersion: http.keda.sh/v1beta1
kind: InterceptorRoute
metadata:
  name: my-app
spec:
  target:
    service: <your-service>
    port: <your-port>
  scalingMetric:
    requestRate:
      targetValue: 100
      window: 1m
      granularity: 1s

Field	Required	Description
`targetValue`	Yes	Target requests per second per replica.
`window`	`1m`	Sliding time window over which the average request rate is calculated.
`granularity`	`1s`	Bucket size within the window. Smaller granularity gives more responsive scaling at the cost of higher sensitivity to bursts.

Using both metrics

An InterceptorRoute can set both concurrency and requestRate. KEDA scales to whichever metric demands more replicas.

apiVersion: http.keda.sh/v1beta1
kind: InterceptorRoute
metadata:
  name: my-app
spec:
  target:
    service: <your-service>
    port: <your-port>
  scalingMetric:
    concurrency:
      targetValue: 50
    requestRate:
      targetValue: 200

This is useful when you want to handle both sustained throughput (rate) and bursty traffic (concurrency).

Scaling boundaries and cooldown

Minimum and maximum replica counts and cooldown are set on the KEDA ScaledObject, not the InterceptorRoute:

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: my-app
spec:
  scaleTargetRef:
    name: <your-deployment>
  minReplicaCount: 0 # 0 enables scale-to-zero
  maxReplicaCount: 10
  cooldownPeriod: 300 # seconds before scaling to zero after traffic stops

Setting minReplicaCount: 0 enables scale-to-zero. The cooldownPeriod controls how long KEDA waits after the last request before scaling the workload down to zero replicas.

What’s Next

How Scaling Works — the full scaling mechanics, including scale-to-zero and cold starts.
InterceptorRoute Reference — field details for scalingMetric, concurrency, and requestRate.