AWS DynamoDB

Scale applications based on the records count in AWS DynamoDB

Availability: v2.7+ Maintainer: Community

Warning

You are currently viewing v"2.7" of the documentation and it is not the latest. For the most recent documentation, kindly click here.

Trigger Specification

This specification describes the AWS DynamoDB scaler. This scaler uses a specified DynamoDB query to determine if and when to scale a given workload.

triggers:
- type: aws-dynamodb
  metadata:
    # Required: awsRegion
    awsRegion: "eu-west-1"
    # Required: tableName
    tableName: myTableName
    # Required: targetValue
    targetValue: "1"
    # Required: expressionAttributeNames
    expressionAttributeNames: '{ "#k" : "partition_key_name"}'
    # Required: keyConditionExpression
    keyConditionExpression: "#k = :key"
    # Required: expressionAttributeValues
    expressionAttributeValues: '{ ":key" : {"S":"partition_key_target_value"}}'
    # Optional. Default: pod
    identityOwner: pod | operator

Parameter list:

awsRegion - AWS Region for the DynamoDB Table.
tableName - The target table where the scaler execute the query.
targetValue - The target value for the number of items retrieved by the query.
expressionAttributeNames - one or more substitution tokens for attribute names in an expression. Defined as JSON.
keyConditionExpression - the condition that specifies the key values for items to be retrieved by the Query action.
expressionAttributeValues - one or more values that can be substituted in an expression. Defined as JSON.
identityOwner - Receive permissions on the DynamoDB Table via Pod Identity or from the KEDA operator itself (see below). (Values: pod, operator, Default: pod, Optional)

When identityOwner set to operator - the only requirement is that the KEDA operator has the correct IAM permissions on the DynamoDB Table. Additional Authentication Parameters are not required.

Authentication Parameters

These parameters are relevant only when identityOwner is set to pod.

You can use TriggerAuthentication CRD to configure the authenticate by providing either a role ARN or a set of IAM credentials.

Pod identity based authentication:

podIdentity.provider - Needs to be set to either aws-kiam or aws-eks on the TriggerAuthentication and the pod/service account must be configured correctly for your pod identity provider.

Role based authentication:

awsRoleArn - Amazon Resource Names (ARNs) uniquely identify AWS resource.

Credential based authentication:

awsAccessKeyID - Id of the user.
awsSecretAccessKey - Access key for the user to authenticate with.
awsSessionToken - Session token, only required when using temporary credentials.

The user will need access to read properties from the specified AWS SQS queue.

Example

Scaling a deployment using IAM Role

apiVersion: v1
kind: Secret
metadata:
  name: test-secrets
data:
  AWS_ROLE_ARN: <encoded-iam-role-arn>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-aws-credentials
  namespace: default
spec:
  secretTargetRef:
  - parameter: awsRoleArn    # The property in KEDA.
    name: test-secrets       # The name of the kubernetes secret.
    key: AWS_ROLE_ARN        # The key from the kubernetes secret.
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name:  aws-dynamodb-table-scaledobject
  namespace: keda-test
spec:
  scaleTargetRef:
    name: nginx-deployment
  triggers:
  - type: aws-dynamodb
    authenticationRef:
      name: keda-trigger-auth-aws-credentials
    metadata:
      awsRegion: eu-west-2
      tableName: keda-events
      expressionAttributeNames: '{ "#k" : "event_type"}'
      keyConditionExpression: "#k = :key"
      expressionAttributeValues: '{ ":key" : {"S":"scaling_event"}}'
      targetValue: "5"

Scaling a deployment using IAM Users

apiVersion: v1
kind: Secret
metadata:
  name: test-secrets
data:
  AWS_ACCESS_KEY_ID: <encoded-user-id> # Required.
  AWS_SECRET_ACCESS_KEY: <encoded-key> # Required.
  AWS_SESSION_TOKEN: <encoded-session-token> # Required when using temporary credentials.
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-aws-credentials
  namespace: default
spec:
  secretTargetRef:
  - parameter: awsAccessKeyID     # Required.
    name: test-secrets            # Required.
    key: AWS_ACCESS_KEY_ID        # Required.
  - parameter: awsSecretAccessKey # Required.
    name: test-secrets            # Required.
    key: AWS_SECRET_ACCESS_KEY    # Required.
  - parameter: awsSessionToken    # Required when using temporary credentials.
    name: test-secrets            # Required when using temporary credentials.
    key: AWS_SESSION_TOKEN        # Required when using temporary credentials.
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name:  aws-dynamodb-table-scaledobject
  namespace: keda-test
spec:
  scaleTargetRef:
    name: nginx-deployment
  triggers:
  - type: aws-dynamodb
    authenticationRef:
      name: keda-trigger-auth-aws-credentials
    metadata:
      awsRegion: eu-west-2
      tableName: keda-events
      expressionAttributeNames: '{ "#k" : "event_type"}'
      keyConditionExpression: "#k = :key"
      expressionAttributeValues: '{ ":key" : {"S":"scaling_event"}}'
      targetValue: "5"