The KEDA Documentation
KEDA Concepts
Operate
Reference
Scalers
Authentication Providers
Integrations

RabbitMQ Queue Click here for latest

Scale applications based on RabbitMQ Queue.

Availability: v1.0+ Maintainer: Microsoft
Scaler code

Suggest a change

Warning

You are currently viewing v2.14 of the documentation and it is not the latest. For the most recent documentation, kindly click here.

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.

âš  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.

âš  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 Registration in Azure AD. In this case username:password part in host URI should be omitted 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