Terraform Module: terraform-module-aws-autoscaling-policy

Terraform Module for AWS AutoScaling Scaling Policy

---

This is a stable example. It should successfully build out of the box

This examples does is built on Construct Libraries marked "Stable" and does not have any infrastructure prerequisites to build.

---

General

This module may be used to create AWS AutoScaling Scaling Policy resources in AWS cloud provider......

---

Prerequisites

This module needs Terraform 0.12.19 or newer. You can download the latest Terraform version from here.

This module deploys aws services details are in respective feature branches.

---

Features

Below we are able to check the resources that are being created as part of this module call:

• AWS AutoScaling Scaling Policy

---

Usage

Using this repo

To use this module, add the following call to your code:

NOTE: You may want to omit desired_capacity attribute from attached aws_autoscaling_group when using autoscaling policies. It's good practice to pick either manual or dynamic (policy-based) scaling.

• Example Usage Simple Scaling

module "autoscaling_policy_up" {
  source = "git::https://github.com/nitinda/terraform-module-aws-autoscaling-policy.git?ref=master"

  providers = {
    aws = aws.services
  }

  name                      = "scal_up"
  scaling_adjustment        = 1
  adjustment_type           = "ChangeInCapacity"
  cooldown                  = 10
  estimated_instance_warmup = 2
  autoscaling_group_name    = module.autoscaling_group.name  
}

• Example Usage Target Scaling

module "autoscaling_policy_up" {
  source = "git::https://github.com/nitinda/terraform-module-aws-autoscaling-policy.git?ref=master"

  providers = {
    aws = aws.services
  }

  name                      = "scal_up"
  adjustment_type           = "ChangeInCapacity"
  estimated_instance_warmup = 2
  autoscaling_group_name    = module.autoscaling_group.name

  target_tracking_configuration = {
    predefined_metric_specification = {
      predefined_metric_type = "ASGAverageCPUUtilization"
    }
    target_value = 40.0
  }
}

• Example Usage Step Scaling

module "autoscaling_policy_up" {
  source = "git::https://github.com/nitinda/terraform-module-aws-autoscaling-policy.git?ref=master"

  providers = {
    aws = aws.services
  }

  name                      = "scal_up"
  adjustment_type           = "ChangeInCapacity"
  estimated_instance_warmup = 2
  autoscaling_group_name    = module.autoscaling_group.name

  step_adjustment = [
    {
      metric_interval_lower_bound = 0
      metric_interval_upper_bound = 50
      scaling_adjustment          = 1
    }.
    {
      metric_interval_lower_bound = 50
      scaling_adjustment          = 2
    }
  ]
}

module "autoscaling_policy_down" {
  source = "git::https://github.com/nitinda/terraform-module-aws-autoscaling-policy.git?ref=master"

  providers = {
    aws = aws.services
  }

  name                      = "scal_up"
  adjustment_type           = "ChangeInCapacity"
  estimated_instance_warmup = 2
  autoscaling_group_name    = module.autoscaling_group.name

  step_adjustment = [
    {
      metric_interval_upper_bound = 0
      scaling_adjustment          = -1
    }
  ]
}

---

Inputs

The variables required in order for the module to be successfully called from the deployment repository are the following:

NOTE: You cannot create a metric alarm consisting of both statistic and extended_statistic parameters. You must choose one or the other

Variable	Description	Type	Argument Status	Default Value
name	The name of the policy	string	Required
autoscaling_group_name	The name of the autoscaling group	string	Required
adjustment_type	Specifies whether the adjustment is an absolute number or a percentage of the current capacity. Valid values are ChangeInCapacity, ExactCapacity, and PercentChangeInCapacity	string	Optional	null
policy_type	The policy type, either "SimpleScaling", "StepScaling" or "TargetTrackingScaling". If this value isn't provided, AWS will default to "SimpleScaling"	string	Optional	SimpleScaling
estimated_instance_warmup	The estimated time, in seconds, until a newly launched instance will contribute CloudWatch metrics. Without a value, AWS will default to the group's specified cooldown period.	number	Optional	null

The following arguments are only available to "SimpleScaling" type policies:

Variable	Description	Type	Argument Status	Default Value
cooldown	The amount of time, in seconds, after a scaling activity completes and before the next scaling activity can start	number	Optional	0
scaling_adjustment	The number of instances by which to scale. adjustment_type determines the interpretation of this number (e.g., as an absolute number or as a percentage of the existing Auto Scaling group size). A positive increment adds to the current capacity and a negative value removes from the current capacity.	string	Optional	null

The following arguments are only available to "StepScaling" type policies:

Variable	Description	Type	Argument Status	Default Value
scaling_adjustment	The aggregation type for the policy's metrics. Valid values are "Minimum", "Maximum", and "Average". Without a value, AWS will treat the aggregation type as "Average".	string	Optional	Average
step_adjustment	A set of adjustments that manage group scaling.	any	Optional	[]

step_adjustment {
    metric_interval_lower_bound = 0
    metric_interval_upper_bound = 50
    scaling_adjustment = 1
}

step_adjustment {
    metric_interval_lower_bound = 50
    scaling_adjustment = 2
}

The following fields are available in step adjustments:

Variable	Description	Type	Argument Status	Default Value
scaling_adjustment	The number of members by which to scale, when the adjustment bounds are breached. A positive value scales up. A negative value scales down.	string	Required
metric_interval_lower_bound	The lower bound for the difference between the alarm threshold and the CloudWatch metric. Without a value, AWS will treat this bound as infinity.	string	Optional	null
metric_interval_upper_bound	The upper bound for the difference between the alarm threshold and the CloudWatch metric. Without a value, AWS will treat this bound as infinity. The upper bound must be greater than the lower bound.	string	Optional	null

The following arguments are only available to "TargetTrackingScaling" type policies:

Variable	Description	Type	Argument Status	Default Value
target_tracking_configuration	A target tracking policy. These have the following structure.	any	Optional	{}

target_tracking_configuration {
  predefined_metric_specification {
    predefined_metric_type = "ASGAverageCPUUtilization"
  }

  target_value = 40.0
}

target_tracking_configuration {
  customized_metric_specification {
    metric_dimension {
      name  = "fuga"
      value = "fuga"
    }

    metric_name = "hoge"
    namespace   = "hoge"
    statistic   = "Average"
  }

  target_value = 40.0
}

---

Outputs

General

This module has the following outputs:

The ARN assigned by AWS to the scaling policy : arn

The scaling policy's name : name

The scaling policy's adjustment type : adjustment_type

The scaling policy's type : policy_type

---

Usage

In order for the variables to be accessed on module level please use the syntax below:

module.<module_name>.<output_variable_name>

The output variable is able to be accessed through terraform state file using the syntax below:

data.terraform_remote_state.<module_name>.<output_variable_name>

---

Authors

Module maintained by Module maintained by the - Nitin Das