NATS Streaming

Scale applications based on NATS Streaming.

Availability: v1.0+ Maintainer: Community

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Trigger Specification

This specification describes the stan trigger for NATS Streaming.

triggers:
- type: stan
  metadata:
    natsServerMonitoringEndpoint: "stan-nats-ss.stan.svc.cluster.local:8222"
    queueGroup: "grp1"
    durableName: "ImDurable"
    subject: "Test"
    lagThreshold: "10"
    activationLagThreshold: "5"
    useHttps: "false"

Parameter list:

natsServerMonitoringEndpoint - Location of the Nats Streaming monitoring endpoint.
queueGroup - Name of queue group of the subscribers.
durableName - Name of durability used by subscribers.
subject - Name of the channel.
lagThreshold - Average target value to trigger scaling actions.
activationLagThreshold - Target value for activating the scaler. Learn more about activation here. (Default: 0, Optional)
useHttps - Specifies if the NATS Streaming monitoring endpoint is using HTTPS. (Default: false, Optional)

Authentication Parameters

You can authenticate with the NATS streaming server by using connection string authentication via TriggerAuthentication configuration.

natsServerMonitoringEndpoint - Location of the NATS Streaming monitoring endpoint.

TLS Authentication

tls - To enable SSL auth for nats-streaming, set this to enable. If not set, TLS for nats-streaming is not used. (Values: enable, disable, Default: disable, Optional)
ca - Certificate authority file for TLS client authentication. (Optional)
cert - Certificate for client authentication. (Optional)
key - Key for client authentication. (Optional)

Example without any TriggerAuthentication

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: stan-scaledobject
  namespace: example
spec:
  pollingInterval: 10   # Optional. Default: 30 seconds
  cooldownPeriod: 30   # Optional. Default: 300 seconds
  minReplicaCount: 0   # Optional. Default: 0
  maxReplicaCount: 30  # Optional. Default: 100
  scaleTargetRef:
    name: gonuts-sub
  triggers:
  - type: stan
    metadata:
      natsServerMonitoringEndpoint: "stan-nats-ss.stan.svc.cluster.local:8222"
      queueGroup: "grp1"
      durableName: "ImDurable"
      subject: "Test"
      lagThreshold: "10"
      useHttps: "false"

Example with no TLS

apiVersion: v1
kind: Secret
metadata:
  name: stan-secret
  namespace: example
type: Opaque
data:
  stan_endpoint: <base-64-encoded-endpoint>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-stan-secret
  namespace: example
spec:
  secretTargetRef:
  - parameter: natsServerMonitoringEndpoint
    name: stan-secret
    key: stan_endpoint
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: stan-scaledobject
  namespace: example
spec:
  pollingInterval: 10   # Optional. Default: 30 seconds
  cooldownPeriod: 30   # Optional. Default: 300 seconds
  minReplicaCount: 0   # Optional. Default: 0
  maxReplicaCount: 30  # Optional. Default: 100
  scaleTargetRef:
    name: gonuts-sub
  triggers:
  - type: stan
    metadata:
      queueGroup: "grp1"
      durableName: "ImDurable"
      subject: "Test"
      lagThreshold: "10"
    authenticationRef:
      name: keda-trigger-auth-stan-secret

Example with TLS

apiVersion: v1
kind: Secret
metadata:
  name: keda-stan-secrets
  namespace: default
data:
  tls: enable
  ca: <your ca>
  cert: <your cert>
  key: <your key>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-stan-secret
  namespace: default
spec:
  secretTargetRef:
    - parameter: tls
      name: keda-stan-secrets
      key: tls
    - parameter: ca
      name: keda-stan-secrets
      key: ca
    - parameter: cert
      name: keda-stan-secrets
      key: cert
    - parameter: key
      name: keda-stan-secrets
      key: key
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: stan-scaledobject
  namespace: example
spec:
  pollingInterval: 10   # Optional. Default: 30 seconds
  cooldownPeriod: 30   # Optional. Default: 300 seconds
  minReplicaCount: 0   # Optional. Default: 0
  maxReplicaCount: 30  # Optional. Default: 100
  scaleTargetRef:
    name: gonuts-sub
  triggers:
  - type: stan
    metadata:
      queueGroup: "grp1"
      durableName: "ImDurable"
      subject: "Test"
      lagThreshold: "10"
      useHttps: "true"
    authenticationRef:
      name: keda-trigger-auth-stan-secret