Apache Pulsar

Scale applications based on an Apache Pulsar topic subscription.

Availability: v2.8 Maintainer: Community

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Trigger Specification

This specification describes the pulsar trigger for an Apache Pulsar topic.

triggers:
- type: pulsar
  metadata:
    adminURL: http://localhost:80
    topic: persistent://public/default/my-topic
    isPartitionedTopic: false
    subscription: sub1
    msgBacklogThreshold: '5'
    activationMsgBacklogThreshold: '2'
    authModes: ""

Parameter list:

adminURL - Stats URL of the admin API for your topic.
topic - Pulsar topic. format of persistent://{tenant}/{namespace}/{topicName}
isPartitionedTopic - Whether the topic is partitioned. When true, the msgBacklogThreshold will be the cumulative subscription backlog across partitions. (default: false, Optional)
subscription - Name of the topic subscription
msgBacklogThreshold - Average target value to trigger scaling actions. (default: 10)
activationMsgBacklogThreshold - Target value for activating the scaler. Learn more about activation here. (Default: 0, Optional)
authModes - a comma separated list of authentication modes to use. (Values: bearer, tls, basic, oauth, Default: "", Optional, tls,bearer or tls,basic are valid combinations and would indicate mutual TLS to secure the connection and then bearer or basic headers should be added to the HTTP request)
oauthTokenURI - The OAuth Access Token URI for the OAuth provider, used when authModes is set to oauth. Ignored if provided from authenticationRef. (Optional)
scope - A comma separated lists of OAuth scopes, used when authModes is set to oauth. Ignored if provided from authenticationRef. (Optional)
clientID - Client ID for the OAuth provider, used when authModes is set to oauth. Ignored if provided from authenticationRef. (Optional)

Authentication Parameters

The authentication is defined in authModes. The associated configuration parameters are specified in the TriggerAuthentication spec.

Bearer Auth

When configuring Bearer Authentication (Token Auth), configure the following:

bearerToken: This token will be sent as a header in the form Authorization: Bearer <token>.

Basic Auth When configuring Basic Authentication, configure the following:

username: the username
password: the password (optional)

TLS:

When configuring mutual TLS authentication, configure the following:

ca: The trusted root Certificate authority used to validate the server’s certificate.
cert: Certificate for client authentication.
key: Key for client authentication.

OAuth 2

When configuring OAuth Authentication, configure the following:

oauthTokenURI - The OAuth Access Token URI for the OAuth provider. (Optional)
scope - A comma separated lists of OAuth scopes. (Optional)
clientID: Client ID for the OAuth provider. (Optional)
clientSecret: Client secret for the OAuth provider. (Optional)

These can also be configured in the trigger metadata except the clientSecret

TLS with custom CA Certificates

When configuring a trusted root CA that is not well known, it is sufficient to specify the ca field on the TriggerAuthentication resource. See Bearer Token with TLS via custom trusted CA Certificate for an example.

Before 2.9.0, it was necessary to configure tls: enable on the ScaledObject. That was removed in a backwards compatible way, so you can remove that field now.

Examples

No Authentication and No TLS

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: pulsar-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: pulsar-consumer
  pollingInterval: 30
  triggers:
  - type: pulsar
    metadata:
      adminURL: http://localhost:80
      topic: persistent://public/default/my-topic
      isPartitionedTopic: false
      subscription: sub1
      msgBacklogThreshold: '5'

Only Mutual TLS Authentication

apiVersion: v1
kind: Secret
metadata:
  name: keda-pulsar-secrets
  namespace: default
data:
  ca: <your ca>
  cert: <your cert>
  key: <your key>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-pulsar-credential
  namespace: default
spec:
  secretTargetRef:
  - parameter: ca
    name: keda-pulsar-secrets
    key: ca
  - parameter: cert
    name: keda-pulsar-secrets
    key: cert
  - parameter: key
    name: keda-pulsar-secrets
    key: key
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: pulsar-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: pulsar-consumer
  pollingInterval: 30
  triggers:
  - type: pulsar
    metadata:
      authModes: "tls"
      adminURL: https://localhost:8443
      topic: persistent://public/default/my-topic
      subscription: sub1
      msgBacklogThreshold: '5'
    authenticationRef:
      name:  keda-trigger-auth-pulsar-credential

Bearer Token with TLS via custom trusted CA Certificate

In order to enable Pulsar’s Token Authentication feature, you can use the following example. Note that this example also utilizes a custom CA Certificate for TLS support. Because TLS Authentication is not used in this example, the authModes field only has bearer.

apiVersion: v1
kind: Secret
metadata:
  name: keda-pulsar-secrets
  namespace: default
data:
  ca: <your self-signed root CA>
  token: <your token>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-pulsar-credential
  namespace: default
spec:
  secretTargetRef:
  - parameter: ca
    name: keda-pulsar-secrets
    key: ca
  - parameter: bearerToken
    name: keda-pulsar-secrets
    key: token
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: pulsar-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: pulsar-consumer
  pollingInterval: 30
  triggers:
  - type: pulsar
    metadata:
      authModes: "bearer"
      adminURL: https://localhost:8443
      topic: persistent://public/default/my-topic
      subscription: sub1
      msgBacklogThreshold: '5'
    authenticationRef:
      name:  keda-trigger-auth-pulsar-credential

Basic Auth with TLS Relying on Well Known Root CA

apiVersion: v1
kind: Secret
metadata:
  name: keda-pulsar-secrets
  namespace: default
data:
  username: <your username>
  password: <your password>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-pulsar-credential
  namespace: default
spec:
  secretTargetRef:
  - parameter: username
    name: keda-pulsar-secrets
    key: admin
  - parameter: password
    name: keda-pulsar-secrets
    key: password
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: pulsar-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: pulsar-consumer
  pollingInterval: 30
  triggers:
  - type: pulsar
    metadata:
      authModes: "bearer"
      adminURL: https://pulsar.com:8443
      topic: persistent://public/default/my-topic
      subscription: sub1
      msgBacklogThreshold: '5'
    authenticationRef:
      name:  keda-trigger-auth-pulsar-credential

OAuth Authentication

In order to enable Pulsar’s OAuth Authentication feature, you can use the following example. Note that only client credentials flow is supported.

apiVersion: v1
kind: Secret
metadata:
  name: keda-pulsar-secrets
  namespace: default
data:
  oauthTokenURI: <your OAuth URI>
  scope: <your Scope>
  clientID: <your clientID>
  clientSecret: <your clientSecret>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-pulsar-credential
  namespace: default
spec:
  secretTargetRef:
  - parameter: oauthTokenURI
    name: keda-pulsar-secrets
    key: oauthTokenURI
  - parameter: scope
    name: keda-pulsar-secrets
    key: scope
  - parameter: clientID
    name: keda-pulsar-secrets
    key: clientID
  - parameter: clientSecret
    name: keda-pulsar-secrets
    key: clientSecret
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: pulsar-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: pulsar-consumer
  pollingInterval: 30
  triggers:
  - type: pulsar
    metadata:
      authModes: "oauth"
      adminURL: https://pulsar.com:8443
      topic: persistent://public/default/my-topic
      subscription: sub1
      msgBacklogThreshold: '5'
    authenticationRef:
      name:  keda-trigger-auth-pulsar-credential

You can also use the following example without authenticationRef if your OAuth provider supports.

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: pulsar-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: pulsar-consumer
  pollingInterval: 30
  triggers:
  - type: pulsar
    metadata:
      authModes: "oauth"
      adminURL: https://pulsar.com:8443
      topic: persistent://public/default/my-topic
      subscription: sub1
      msgBacklogThreshold: '5'
      oauthTokenURI: http://oauth.com/oauth2/token
      scope: <your scope>
      clientID: <your clientID>