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Scale applications based on the count of objects in a given OpenStack Swift container.

Availability: v2.1+ Maintainer: Community

Trigger Specification

This specification describes the openstack-swift trigger for OpenStack Swift containers. It scales based on the count of objects in a given container.

triggers:
- type: openstack-swift
  metadata:
    containerName: my-container # Required
    swiftURL: http://localhost:8080/v1/b161dc815cd24bda84d94d9a0e73cf78  # Optional
    objectCount: "2"  # Optional
    objectPrefix: "my-prefix" # Optional
    objectDelimiter: "/"  # Optional 
    objectLimit: "10" # Optional
    onlyFiles: "true" # Optional
    timeout: "2"  # Optional

Please, always provide the protocol (http or https) when specifying URLs.

Parameter list:

  • swiftURL - The URL to query the Swift API. If not provided, the scaler will try to find the Swift public URL for a certain region, using the OpenStack catalog, which is returned when requesting an authentication token.
  • containerName - Name of Swift container in an OpenStack account
  • objectCount - Average target value to trigger scaling actions. If not specified, the default value is 2
  • objectPrefix - Prefix for the object. Only objects with this prefix will be returned. Use this prefix to specify sub-paths for the objects, if required. If not specified, the default value is "".
  • objectDelimiter - Delimiter for identifying the object prefix. It is the character used to split object names. The default value is "".
  • objectLimit - The maximum number of objects returned by the API. By default, the Swift API only returns up to 10000 names. The default value is "", which will use the Swift API standard limit. Negative values default to the Swift API standard limit.
  • onlyFiles - Boolean value that specifies if the scaler should be triggered only by the number of files, without considering folders. Inside a container, one can have files and folders. Folders (empty or not) are counted as objects, just as files are. If one wants to scale based on only files, this parameter must be set to true. The default value is false.
  • timeout - The timeout, in seconds, for the HTTP client requests that will query the Swift API. If not specified, the default value is 30 seconds. This must be an integer value. If 0 or negative value is provided it defaults to 300 milliseconds.

For more information about prefix, delimiter, and limit, please, refer to the Object Store API.

Authentication Parameters

To authenticate, this scaler uses tokens. Tokens are automatically retrieved by the scaler from Keystone, the official OpenStack Identity Provider. You can provide your credentials using Secrets either by using the “password” method or the “application credentials” method. Both cases use TriggerAuthentication.

Password

  • authURL - The Keystone authentication URL. The scaler supports only Keystone v3. You shouldn’t include the /v3 parameter in your URL path. This is done automatically by the scaler.
  • userID - The OpenStack project user ID
  • password - The password for the provided user
  • projectID - The OpenStack project ID
  • regionName - The OpenStack region name where the Swift service is available. This parameter is not required and is used only when the swiftURL is not provided to the scaler. If the region name is not provided, it will look for the first Swift public URL available in the OpenStack catalog.

Application Credentials

  • authURL - The Keystone authentication URL. The scaler supports only Keystone v3. You shouldn’t include the /v3 parameter in your URL path. This is done automatically by the scaler.
  • appCredentialID - The Application Credential ID
  • appCredentialSecret - The Application Credential secret
  • regionName - The OpenStack region name where the Swift service is available. This parameter is not required and is used only when the swiftURL is not provided to the scaler. If the region name is not provided, it will look for the first Swift public URL available in the OpenStack catalog.

Example

Password method

Here is an example of how to deploy a scaled object with the openstack-swift scale trigger which uses TriggerAuthentication and the Password method from above.

apiVersion: v1
kind: Secret
metadata:
  name: openstack-secret-password
  namespace: default
type: Opaque
data:
  authURL: aHR0cDovL2xvY2FsaG9zdDo1MDAwLw==
  userID: MWYwYzI3ODFiNDExNGQxM2E0NGI4ODk4Zjg1MzQwYmU=
  password: YWRtaW4=
  projectID: YjE2MWRjNTE4Y2QyNGJkYTg0ZDk0ZDlhMGU3M2ZjODc=
  regionName: Y2FsaWZvcm5pYS0x
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: swift-password-trigger-authentication
  namespace: default
spec:
  secretTargetRef:
  - parameter: authURL
    name: openstack-secret-password
    key: authURL
  - parameter: userID
    name: openstack-secret-password
    key: userID
  - parameter: password
    name: openstack-secret-password
    key: password
  - parameter: projectID
    name: openstack-secret-password
    key: projectID
  - parameter: regionName
    name: openstack-secret-password
    key: regionName
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: swift-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: my-deployment
  pollingInterval: 10
  cooldownPeriod: 10
  minReplicaCount: 0
  triggers:
  - type: openstack-swift
    metadata:
      containerName: my-container
      objectCount: "1"
      onlyFiles: "true"
    authenticationRef:
        name: swift-password-trigger-authentication

Application Credentials method

You can also use the Application Credentials method.

apiVersion: v1
kind: Secret
metadata:
  name: openstack-secret-appcredentials
  namespace: default
type: Opaque
data:
  authURL: aHR0cDovL2xvY2FsaG9zdDo1MDAwLw==
  appCredentialID: OWYyY2UyYWRlYmFkNGQxNzg0NTgwZjE5ZTljMTExZTQ=
  appCredentialSecret: LVdSbFJBZW9sMm91Z3VmZzNEVlBqcll6aU9za1pkZ3c4Y180XzRFU1pZREloT0RmajJkOHg0dU5yb3NudVIzWmxDVTZNLTVDT3R5NDFJX3M5R1N5Wnc=
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: swift-appcredentials-trigger-authentication
  namespace: default
spec:
  secretTargetRef:
  - parameter: authURL
    name: openstack-secret-appcredentials
    key: authURL
  - parameter: appCredentialID
    name: openstack-secret-appcredentials
    key: appCredentialID
  - parameter: appCredentialSecret
    name: openstack-secret-appcredentials
    key: appCredentialSecret
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: swift-scaledobject
  namespace: default
spec:
  scaleTargetRef:
    name: my-deployment
  pollingInterval: 10
  cooldownPeriod: 10
  minReplicaCount: 0
  triggers:
  - type: openstack-swift
    metadata:
      swiftURL: http://localhost:8080/v1/AUTH_b161dc518cd24bda84d94d9a0e73fc87
      containerName: my-container
      objectCount: "1"
    authenticationRef:
        name: swift-appcredentials-trigger-authentication


Currently available scalers for KEDA