Prometheus | KEDA

Scale applications based on Prometheus.

Availability: v1.0+ Maintainer: Community

Warning

You are currently viewing v"2.5" of the documentation and it is not the latest. For the most recent documentation, kindly click here.

Trigger Specification

This specification describes the prometheus trigger that scales based on a Prometheus.

triggers:
- type: prometheus
  metadata:
    # Required fields:
    serverAddress: http://<prometheus-host>:9090
    metricName: http_requests_total # Note: name to identify the metric, generated value would be `prometheus-http_requests_total`
    query: sum(rate(http_requests_total{deployment="my-deployment"}[2m])) # Note: query must return a vector/scalar single element response
    threshold: '100'

Parameter list:

serverAddress - Address of Prometheus server. If using VictoriaMetrics cluster version, set full URL to Prometheus querying API, e.g. http://<vmselect>:8481/select/0/prometheus
metricName - Name to identify the Metric in the external.metrics.k8s.io API. If using more than one trigger it is required that all metricName(s) be unique.
query - Query to run.
threshold - Value to start scaling for.

Authentication Parameters

Prometheus Scaler supports three types of authentication - bearer authentication, basic authentication and TLS authentication.

You can use TriggerAuthentication CRD to configure the authentication. It is possible to specify multiple authentication types i.e. authModes: "tls,basic" Specify authModes and other trigger parameters along with secret credentials in TriggerAuthentication as mentioned below:

Bearer authentication:

authModes: It must contain bearer in case of Bearer Authentication. Specify this in trigger configuration.
bearerToken: The token needed for authentication. This is a required field.

Basic authentication:

authModes: It must contain basic in case of Basic Authentication. Specify this in trigger configuration.
username - This is a required field. Provide the username to be used for basic authentication.
password - Provide the password to be used for authentication. For convenience, this has been marked optional, because many applications implement basic auth with a username as apikey and password as empty.

TLS authentication:

authModes: It must contain tls in case of TLS Authentication. Specify this in trigger configuration.
ca - Certificate authority file for TLS client authentication.
cert - Certificate for client authentication. This is a required field.
key - Key for client authentication. Optional. This is a required field.

💡 **NOTE:**It’s also possible to set the CA certificate regardless of the selected authModes (also without any authentication). This might be useful if you are using an enterprise CA.

Example

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: prometheus-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: my-deployment
  triggers:
  - type: prometheus
    metadata:
      serverAddress: http://<prometheus-host>:9090
      metricName: http_requests_total
      threshold: '100'
      query: sum(rate(http_requests_total{deployment="my-deployment"}[2m]))

Here is an example of a prometheus scaler with Basic Authentication, define the Secret and TriggerAuthentication as follows

apiVersion: v1
kind: Secret
metadata:
  name: keda-prom-secret
  namespace: default
data:
  bearerToken: "BEARER_TOKEN"
  ca: "CUSTOM_CA_CERT"
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-prom-creds
  namespace: default
spec:
  secretTargetRef:
    - parameter: bearerToken
      name: keda-prom-secret
      key: bearerToken
      # might be required if you're using a custom CA
    - parameter: ca
      name: keda-prom-secret
      key: ca
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: prometheus-scaledobject
  namespace: keda
  labels:
    deploymentName: dummy
spec:
  maxReplicaCount: 12
  scaleTargetRef:
    name: dummy
  triggers:
    - type: prometheus
      metadata:
        serverAddress: http://<prometheus-host>:9090
        metricName: http_requests_total
        threshold: '100'
        query: sum(rate(http_requests_total{deployment="my-deployment"}[2m]))
        authModes: "bearer"
      authenticationRef:
        name: keda-prom-creds

Here is an example of a prometheus scaler with Basic Authentication, define the Secret and TriggerAuthentication as follows

apiVersion: v1
kind: Secret
metadata:
  name: keda-prom-secret
  namespace: default
data:
  username: "dXNlcm5hbWUK" # Must be base64
  password: "cGFzc3dvcmQK"
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-prom-creds
  namespace: default
spec:
  secretTargetRef:
    - parameter: username
      name: keda-prom-secret
      key: username
    - parameter: password
      name: keda-prom-secret
      key: password
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: prometheus-scaledobject
  namespace: keda
  labels:
    deploymentName: dummy
spec:
  maxReplicaCount: 12
  scaleTargetRef:
    name: dummy
  triggers:
    - type: prometheus
      metadata:
        serverAddress: http://<prometheus-host>:9090
        metricName: http_requests_total
        threshold: '100'
        query: sum(rate(http_requests_total{deployment="my-deployment"}[2m]))
        authModes: "basic"
      authenticationRef:
        name: keda-prom-creds

Here is an example of a prometheus scaler with TLS Authentication, define the Secret and TriggerAuthentication as follows

apiVersion: v1
kind: Secret
metadata:
  name: keda-prom-secret
  namespace: default
data:
  cert: "cert"
  key: "key"
  ca: "ca"
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-prom-creds
  namespace: default
spec:
  secretTargetRef:
    - parameter: cert
      name: keda-prom-secret
      key: cert
    - parameter: key
      name: keda-prom-secret
      key: key
    - parameter: ca
      name: keda-prom-secret
      key: ca
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: prometheus-scaledobject
  namespace: keda
  labels:
    deploymentName: dummy
spec:
  maxReplicaCount: 12
  scaleTargetRef:
    name: dummy
  triggers:
    - type: prometheus
      metadata:
        serverAddress: http://<prometheus-host>:9090
        metricName: http_requests_total
        threshold: '100'
        query: sum(rate(http_requests_total{deployment="my-deployment"}[2m]))
        authModes: "tls"
      authenticationRef:
        name: keda-prom-creds

Here is an example of a prometheus scaler with TLS and Basic Authentication, define the Secret and TriggerAuthentication as follows

apiVersion: v1
kind: Secret
metadata:
  name: keda-prom-secret
  namespace: default
data:
  cert: "cert"
  key: "key"
  ca: "ca"
  username: "username"
  password: "password"
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-prom-creds
  namespace: default
spec:
  secretTargetRef:
    - parameter: cert
      name: keda-prom-secret
      key: cert
    - parameter: key
      name: keda-prom-secret
      key: key
    - parameter: ca
      name: keda-prom-secret
      key: ca
    - parameter: username
      name: keda-prom-secret
      key: username
    - parameter: password
      name: keda-prom-secret
      key: password
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: prometheus-scaledobject
  namespace: keda
  labels:
    deploymentName: dummy
spec:
  maxReplicaCount: 12
  scaleTargetRef:
    name: dummy
  triggers:
    - type: prometheus
      metadata:
        serverAddress: http://<prometheus-host>:9090
        metricName: http_requests_total
        threshold: '100'
        query: sum(rate(http_requests_total{deployment="my-deployment"}[2m]))
        authModes: "tls,basic"
      authenticationRef:
        name: keda-prom-creds