The KEDA Documentation
KEDA Concepts
Operate
Scalers
Authentication Providers
Integrations

Prometheus Click here for latest

Scale applications based on Prometheus.

Availability: v1.0+ Maintainer: Community
Scaler code

Suggest a change

Warning

You are currently viewing v2.5 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