NATS Streaming

Scale applications based on NATS Streaming.

Availability: v1.0+ Maintainer: Community

Warning

You are currently viewing v"2.15" of the documentation and it is not the latest. For the most recent documentation, kindly click here.

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