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Scale applications based on RabbitMQ Queue.

Availability: v1.0+ Maintainer: Microsoft
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Trigger Specification

This specification describes the rabbitmq trigger for RabbitMQ Queue.

triggers:
- type: rabbitmq
  metadata:
    host: amqp://localhost:5672/vhost # Optional. If not specified, it must be done by using TriggerAuthentication.
    protocol: auto # Optional. Specifies protocol to use, either amqp or http, or auto to autodetect based on the `host` value. Default value is auto.
    mode: QueueLength # QueueLength or MessageRate
    value: "100.50" # message backlog or publish/sec. target per instance
    activationValue: "10.5" # Optional. Activation threshold
    queueName: testqueue
    vhostName: / # Optional. If not specified, use the vhost in the `host` connection string. Required for Azure AD Workload Identity authorization (see bellow)
    # Alternatively, you can use existing environment variables to read configuration from:
    # See details in "Parameter list" section
    hostFromEnv: RABBITMQ_HOST # Optional. You can use this instead of `host` parameter
    unsafeSsl: true

Parameter list:

  • host - Host of RabbitMQ with format <protocol>://<host>:<port>/vhost. If the protocol is HTTP than the host may follow this format http://<host>:<port>/<path>/<vhost>. In example the resolved host value could be amqp://guest:password@localhost:5672/vhost or http://guest:password@localhost:15672/path/vhost. If the host doesn’t contain vhost than the trailing slash is required in this case like http://guest:password@localhost:5672/. When using a username/password consider using hostFromEnv or a TriggerAuthentication.
  • queueName - Name of the queue to read message from.
  • mode - QueueLength to trigger on number of messages in the queue. MessageRate to trigger on the published rate into the queue. (Values: QueueLength, MessageRate)
  • value - Message backlog or Publish/sec. rate to trigger on. (This value can be a float when mode: MessageRate)
  • activationValue - Target value for activating the scaler. Learn more about activation here.(Default: 0, Optional, This value can be a float)
  • protocol - Protocol to be used for communication. (Values: auto, http, amqp, Default: auto, Optional)
  • vhostName - Vhost to use for the connection, overrides any vhost set in the connection string from host/hostFromEnv. (Optional / Required if Azure AD Workload Identity authorization is used)
  • queueLength - DEPRECATED! Use mode: QueueLength and value: ## instead. Target value for queue length passed to the scaler. Example: if one pod can handle 10 messages, set the queue length target to 10. If the actual number of messages in the queue is 30, the scaler scales to 3 pods. Default is 20 unless publishRate is specified, in which case queueLength is disabled for this trigger.
  • useRegex - This parameter allows to use regex (in queueName parameter) to select queue instead of full name. (Values: true, false, Default: false, Optional, Only applies to hosts that use the http protocol)
  • pageSize - This parameter allows setting page size. (Default: 100, Optional, Only applies when useRegex is true)
  • operation - Operation that will be applied to compute the number of messages in case of useRegex enabled. Either sum (default),max, or avg. (Optional)
  • timeout - Timeout for this specific trigger. This value will override the value defined in KEDA_HTTP_DEFAULT_TIMEOUT. (Optional, Only applies to hosts that use the http protocol)
  • excludeUnacknowledged - Set to true to specify that the QueueLength value should exclude unacknowledged messages (Ready messages only). (Values: true, false, Default: false, Optional, Only applies to hosts that use the http protocol)
  • unsafeSsl - Whether to allow unsafe SSL (Values: true, false, Default: false )

Some parameters could be provided using environmental variables, instead of setting them directly in metadata. Here is a list of parameters you can use to retrieve values from environment variables:

  • hostFromEnv - The host and port of the RabbitMQ server, similar to host, but reads it from an environment variable on the scale target.

💡 Note: host/hostFromEnv has an optional vhost name after the host slash which will be used to scope API request.

💡 Note: When using host/hostFromEnv or TriggerAuthentication, the supplied password cannot contain special characters.

💡 Note: mode: MessageRate requires protocol http.

💡 Note: useRegex: "true" requires protocol http.

⚠ Important: if you have unacknowledged messages and want to have these counted for the scaling to happen, make sure to utilize the http REST API interface which allows for these to be counted.

⚠ Important: If scaling against both is desired then the ScaledObject should have two triggers, one for mode: QueueLength and the other for mode: MessageRate. HPA will scale based on the largest result considering each of the two triggers independently.

Authentication Parameters

TriggerAuthentication CRD is used to connect and authenticate to RabbitMQ:

  • For AMQP, the URI should look similar to amqp://guest:password@localhost:5672/vhost.
  • For HTTP, the URI should look similar to http://guest:password@localhost:15672/path/vhost.

See the RabbitMQ Ports section for more details on how to configure the ports.

TLS authentication:

  • tls - To enable SSL auth for RabbitMQ, set this to enable. If not set, TLS for RabbitMQ 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)

Using RabbitMQ host with amqps will require enabling the tls settings and passing the required parameters.

Azure Workload Identity authentication:

For RabbitMQ with OIDC support (>= 3.11) you can use TriggerAuthentication CRD with podIdentity.provider = azure-workload and with parameter workloadIdentityResource which would hold application identifier of App Registraion in Azure AD. In this case username:password part in host URI should be ommited and vHostName has to be set explicitly in ScaledObject. Only HTTP protocol is supported for AKS Workload Identity currently.

Example

AMQP protocol: 

apiVersion: v1
kind: Secret
metadata:
  name: keda-rabbitmq-secret
data:
  host: <AMQP URI connection string> # base64 encoded value of format amqp://guest:password@localhost:5672/vhost
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-rabbitmq-conn
  namespace: default
spec:
  secretTargetRef:
    - parameter: host
      name: keda-rabbitmq-secret
      key: host
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: rabbitmq-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: rabbitmq-deployment
  triggers:
  - type: rabbitmq
    metadata:
      protocol: amqp
      queueName: testqueue
      mode: QueueLength
      value: "20"
    authenticationRef:
      name: keda-trigger-auth-rabbitmq-conn

AMQPS protocol with TLS auth: 

apiVersion: v1
kind: Secret
metadata:
  name: keda-rabbitmq-secret
data:
  host: <AMQPS URI connection string> # base64 encoded value of format amqps://guest:password@localhost:5672/vhost
  tls: "enable"
  ca: <your ca>
  cert: <your cert>
  key: <your key>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-rabbitmq-conn
  namespace: default
spec:
  secretTargetRef:
    - parameter: host
      name: keda-rabbitmq-secret
      key: host
    - parameter: tls
      name: keda-rabbitmq-secret
      key: tls
    - parameter: ca
      name: keda-rabbitmq-secret
      key: ca
    - parameter: cert
      name: keda-rabbitmq-secret
      key: cert
    - parameter: key
      name: keda-rabbitmq-secret
      key: key
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: rabbitmq-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: rabbitmq-deployment
  triggers:
  - type: rabbitmq
    metadata:
      protocol: amqp
      queueName: testqueue
      mode: QueueLength
      value: "20"
    authenticationRef:
      name: keda-trigger-auth-rabbitmq-conn

HTTP protocol (QueueLength): 

apiVersion: v1
kind: Secret
metadata:
  name: keda-rabbitmq-secret
data:
  host: <HTTP API endpoint> # base64 encoded value of format http://guest:password@localhost:15672/path/vhost
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-rabbitmq-conn
  namespace: default
spec:
  secretTargetRef:
    - parameter: host
      name: keda-rabbitmq-secret
      key: host
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: rabbitmq-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: rabbitmq-deployment
  triggers:
  - type: rabbitmq
    metadata:
      protocol: http
      queueName: testqueue
      mode: QueueLength
      value: "20"
    authenticationRef:
      name: keda-trigger-auth-rabbitmq-conn

HTTP protocol (MessageRate and QueueLength): 

apiVersion: v1
kind: Secret
metadata:
  name: keda-rabbitmq-secret
data:
  host: <HTTP API endpoint> # base64 encoded value of format http://guest:password@localhost:15672/path/vhost
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-rabbitmq-conn
  namespace: default
spec:
  secretTargetRef:
    - parameter: host
      name: keda-rabbitmq-secret
      key: host
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: rabbitmq-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: rabbitmq-deployment
  triggers:
  - type: rabbitmq
    metadata:
      protocol: http
      queueName: testqueue
      mode: QueueLength
      value: "20"
    authenticationRef:
      name: keda-trigger-auth-rabbitmq-conn
  - type: rabbitmq
    metadata:
      protocol: http
      queueName: testqueue
      mode: MessageRate
      value: "100"
    authenticationRef:
      name: keda-trigger-auth-rabbitmq-conn

HTTP protocol (QueueLength) and using regex (useRegex): 

apiVersion: v1
kind: Secret
metadata:
  name: keda-rabbitmq-secret
data:
  host: <HTTP API endpoint> # base64 encoded value of format http://guest:password@localhost:15672/path/vhost
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-rabbitmq-conn
  namespace: default
spec:
  secretTargetRef:
    - parameter: host
      name: keda-rabbitmq-secret
      key: host
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: rabbitmq-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: rabbitmq-deployment
  triggers:
  - type: rabbitmq
    metadata:
      protocol: http
      queueName: ^.*incoming$
      mode: QueueLength
      value: "20"
      useRegex: "true"
      operation: max
    authenticationRef:
      name: keda-trigger-auth-rabbitmq-conn

HTTP protocol (QueueLength) with Azure Workload Identity: 

apiVersion: v1
kind: Secret
metadata:
  name: keda-rabbitmq-secret
data:
  host: <HTTP API endpoint> # base64 encoded value of format http://localhost:15672/ !! no password !!
  clientId: <RabbitMQ AzureAD App Registration Client ID> # base64 encoded value of Client ID (same as for Rabbit's auth_oauth2.resource_server_id)
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-rabbitmq-conn
  namespace: default
spec:
  podIdentity:
    provider: azure-workload
  secretTargetRef:
    - parameter: host
      name: keda-rabbitmq-secret
      key: host
    - parameter: workloadIdentityResource
      name: keda-rabbitmq-secret
      key: clientId
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: rabbitmq-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: rabbitmq-deployment
  triggers:
  - type: rabbitmq
    metadata:
      protocol: http
      vHostName: /
      queueName: testqueue
      mode: QueueLength
      value: "20"
    authenticationRef:
      name: keda-trigger-auth-rabbitmq-conn