External | KEDA

Scale applications based on an external scaler.

Availability: v1.0+ Maintainer: Microsoft

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Trigger Specification

This specification describes the external trigger for an external scaler.

triggers:
- type: external
  metadata:
    scalerAddress: external-scaler-service:8080
    caCert : /path/to/tls/ca.pem
    tlsCertFile: /path/to/tls/cert.pem # Deprecated. https://github.com/kedacore/keda/issues/4549
    tlsClientCert: /path/to/tls/cert.pem
    tlsClientKey: /path/to/tls/key.pem
    unsafeSsl: false

Parameter list:

scalerAddress - Address of the external scaler. Format must be host:port.
tlsCertFile - Location of a certificate to use for the GRPC connection to authenticate with. (Optional)
unsafeSsl - Skip certificate validation when connecting over HTTPS. (Values: true, false, Default: false, Optional)

The entire metadata object is passed to the external scaler in ScaledObjectRef.scalerMetadata.

For implementing an external scaler, refer to External Scalers Concept.

Authentication Parameters

caCert - Certificate Authority (CA) certificate to use for the GRPC connection to authenticate with. (Optional)
tlsClientCert - Client certificate to use for the GRPC connection to authenticate with. (Optional)
tlsClientKey - Client private key to use for the GRPC connection to authenticate with. (Optional)

Example

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: external-scaledobject
spec:
  scaleTargetRef:
    name: keda-redis-node
  triggers:
  - type: external
    metadata:
      scalerAddress: redis-external-scaler-service:8080
      address: REDIS_HOST
      password: REDIS_PASSWORD
      listName: mylist
      listLength: "5"

Here is an example of external scaler with certificates

apiVersion: v1
kind: Secret
metadata:
  name: certificate
data:
  ca.crt: "YOUR_CA_IN_SECRET"
  tls.crt: "YOUR_CERTIFICATE_IN_SECRET"
  tls.key: "YOUR_KEY_IN_SECRET"
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth
spec:
  secretTargetRef:
  - parameter: caCert
    name: certificate
    key: ca.crt
  - parameter: tlsClientCert
    name: certificate
    key: tls.crt
  - parameter: tlsClientKey
    name: certificate
    key: tls.key
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: external-scaledobject
spec:
  scaleTargetRef:
    name: keda-redis-node
  triggers:
  - type: external
    metadata:
      scalerAddress: redis-external-scaler-service:8080
      metricType: mymetric
      scalerAddress: mydomain.com:443
      extraKey: "demo"
    authenticationRef:
      name: keda-trigger-auth