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 MB or lower than 2 MB over a period of five minutes. To use Amazon EC2 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.
For more information about CloudWatch metrics and alarms, see Amazon CloudWatch Concepts in the Amazon CloudWatch User Guide.
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
Open the Elastic Beanstalk console
, and in the Regions list, select your AWS Region. -
In the navigation pane, choose Environments, and then choose the name of your environment from the list.
Note
If you have many environments, use the search bar to filter the environment list.
In the navigation pane, choose Configuration.
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In the Capacity configuration category, choose Edit.
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In the Scaling triggers section, configure the following settings:
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Metric – Metric used for your Auto Scaling trigger.
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Statistic – Statistic calculation the trigger should use, such as
Average. -
Unit – Unit for the trigger metric, such as Bytes.
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Period – Specifies how frequently Amazon CloudWatch measures the metrics for your trigger.
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Breach duration – Amount of time, in minutes, a metric can be outside of the upper and lower thresholds before triggering a scaling operation.
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Upper threshold – If the metric exceeds this number for the breach duration, a scaling operation is triggered.
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Scale up increment – The number of Amazon EC2 instances to add when performing a scaling activity.
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Lower threshold – If the metric falls below this number for the breach duration, a scaling operation is triggered.
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Scale down increment – The number of Amazon EC2 instances to remove when performing a scaling activity.
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To save the changes choose Apply at the bottom of the page.
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