AWS CloudWatch

Scale applications based on AWS CloudWatch.

Availability: v1.0+ Maintainer: Community

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Trigger Specification

This specification describes the aws-cloudwatch trigger that scales based on a AWS CloudWatch.

triggers:
- type: aws-cloudwatch
  metadata:
    # Required: namespace
    namespace: AWS/SQS
    # Required: Dimension Name - Supports specifying multiple dimension names by using ";" as a separator i.e. dimensionName: QueueName;QueueName
    dimensionName: QueueName
    # Required: Dimension Value - Supports specifying multiple dimension values by using ";" as a separator i.e. dimensionValue: queue1;queue2
    dimensionValue: keda
    metricName: ApproximateNumberOfMessagesVisible
    targetMetricValue: "2"
    minMetricValue: "0"
    # Required: region
    awsRegion: "eu-west-1"
    # Optional: AWS Access Key ID, can use TriggerAuthentication as well
    awsAccessKeyIDFromEnv: AWS_ACCESS_KEY_ID # default AWS_ACCESS_KEY_ID
    # Optional: AWS Secret Access Key, can use TriggerAuthentication as well
    awsSecretAccessKeyFromEnv: AWS_SECRET_ACCESS_KEY # default AWS_SECRET_ACCESS_KEY
    identityOwner: pod | operator # Optional. Default: pod
    # Optional: Metric Collection Time
    metricCollectionTime: "300" # default 300
    # Optional: Metric Statistic
    metricStat: "Average" # default "Average"
    # Optional: Metric Statistic Period
    metricStatPeriod: "300" # default 300

Parameter list:

identityOwner - Receive permissions on the CloudWatch 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 CloudWatch. Additional Authentication Parameters are not required.

metricCollectionTime - How long in the past (seconds) should the scaler check AWS Cloudwatch. Used to define StartTime (official documentation). (Default: 300, Optional)
metricStat - Which statistics metric is going to be used by the query. Used to define Stat (official documentation). (Default: Average, Optional)
metricStatPeriod - Which frequency is going to be used by the related query. Used to define Period (official documentation). (Default: 300, Optional)

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.

The user will need access to read data from AWS CloudWatch.

IAM Permissions

The user or role used to authenticate with AWS CloudWatch must have the cloudwatch:GetMetricData permissions. The following is an example IAM policy that grants the necessary permissions to read data from CloudWatch:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowCloudWatchGetMetricData",
      "Effect": "Allow",
      "Action": "cloudwatch:GetMetricData",
      "Resource": "*"
    }
  ]
}

This can be further scoped to specific namespaces, by using the cloudwatch:namespace condition key. For example, to only allow access to the AWS/EC2 metric namespace:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowCloudWatchGetMetricData",
      "Effect": "Allow",
      "Action": "cloudwatch:GetMetricData",
      "Resource": "*",
      "Condition": {
        "StringEquals": {
          "cloudwatch:namespace": "AWS/EC2"
        }
      }
    }
  ]
}

For more information, see the AWS CloudWatch IAM documentation.

Example

apiVersion: v1
kind: Secret
metadata:
  name: test-secrets
data:
  AWS_ACCESS_KEY_ID: <encoded-user-id>
  AWS_SECRET_ACCESS_KEY: <encoded-key>
---
apiVersion: keda.sh/v1alpha1
kind: TriggerAuthentication
metadata:
  name: keda-trigger-auth-aws-credentials
  namespace: keda-test
spec:
  secretTargetRef:
  - parameter: awsAccessKeyID     # Required.
    name: keda-aws-secrets        # Required.
    key: AWS_ACCESS_KEY_ID        # Required.
  - parameter: awsSecretAccessKey # Required.
    name: keda-aws-secrets        # Required.
    key: AWS_SECRET_ACCESS_KEY    # Required.
---
apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  name: aws-cloudwatch-queue-scaledobject
  namespace: keda-test
spec:
  scaleTargetRef:
    name: nginx-deployment
  triggers:
  - type: aws-cloudwatch
    metadata:
      namespace: AWS/SQS
      dimensionName: QueueName
      dimensionValue: keda
      metricName: ApproximateNumberOfMessagesVisible
      targetMetricValue: "2"
      minMetricValue: "0"
      awsRegion: "eu-west-1"
    authenticationRef:
      name: keda-trigger-auth-aws-credentials