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AWS Elastic Beanstalk
Developer Guide (API Version 2010-12-01)

Auto Scaling Triggers

The Auto Scaling group in your Elastic Beanstalk environment uses two Amazon CloudWatch alarms to trigger scaling operations. The default triggers scale when the average outbound network traffic from each instance is higher than 6 MiB or lower than 2 MiB over a period of 5 minutes. To use Auto Scaling effectively, configure triggers that are appropriate for your application, instance type, and service requirements. You can scale based on several statistics including latency, disk I/O, CPU utilization, and request count.

Configuring Auto Scaling Triggers

You can configure the triggers that adjust the number of instances in your environment's Auto Scaling group in the Elastic Beanstalk console.

To configure triggers in the Elastic Beanstalk console

  1. Open the Elastic Beanstalk console.

  2. Navigate to the management page for your environment.

  3. Choose Configuration.

  4. Choose Scaling.

  5. Expand the Scaling Trigger section.

    
            Elastic Beanstalk Auto Scaling Triggers Configuration Window
  6. Configure the following options.

    • Trigger measurement – Metric used for your Auto Scaling trigger.

    • Trigger statistic – Statistic the trigger should use, such as Average.

    • Unit of measurement – Unit for the trigger measurement, such as Bytes.

    • Measurement period – Specifies how frequently Amazon CloudWatch measures the metrics for your trigger.

    • Breach duration – Amount of time, in minutes, a metric can be beyond outside of the upper and lower thresholds before the trigger fires.

    • Upper threshold – If the measurement is higher than this number for the breach duration, a trigger is fired.

    • Upper breach scale increment – How many Amazon EC2 instances to add when performing a scaling activity.

    • Lower threshold – If the measurement falls below this number for the breach duration, a trigger is fired.

    • Lower breach scale increment – How many Amazon EC2 instances to remove when performing a scaling activity.

  7. Choose Apply.

The aws:autoscaling:trigger Namespace

Elastic Beanstalk provides configuration options for Auto Scaling settings in the aws:autoscaling:trigger namespace. Settings in this namespace are organized by the resource that they apply to.

option_settings:
  AWSEBAutoScalingScaleDownPolicy.aws:autoscaling:trigger:
    LowerBreachScaleIncrement: '-1'
  AWSEBAutoScalingScaleUpPolicy.aws:autoscaling:trigger:
    UpperBreachScaleIncrement: '1'
  AWSEBCloudwatchAlarmHigh.aws:autoscaling:trigger:
    UpperThreshold: '6000000'
  AWSEBCloudwatchAlarmLow.aws:autoscaling:trigger:
    BreachDuration: '5'
    EvaluationPeriods: '1'
    LowerThreshold: '2000000'
    MeasureName: NetworkOut
    Period: '5'
    Statistic: Average
    Unit: Bytes