Amazon EC2 Auto Scaling

Overview

The AWS Auto Scaling Module provides a reusable and scalable way to provision and manage Amazon EC2 Auto Scaling infrastructure using Terraform.
It abstracts the complexity of configuring Auto Scaling resources and enables developers to define infrastructure with minimal effort while following AWS best practices.

This module supports both resource creation and data sources for managing Auto Scaling Groups (ASG), Launch Configurations, and related policies.

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Features

• 🚀 Reusable & Modular – Predefined structure for resources and data modules.
• 📈 Dynamic Scaling – Configure scaling policies based on CPU, memory, or custom CloudWatch metrics.
• 🔄 Lifecycle Hooks – Supports lifecycle events for custom workflows during instance launch/termination.
• 🧑‍🤝‍🧑 Multiple Attachments – Attach Auto Scaling groups to multiple target groups or load balancers.
• 📜 Tagging & Notifications – Supports group tags and SNS notifications for scaling activities.
• ⏱ Scheduled Scaling – Define scheduled actions for predictable workload changes.
• 🧩 Extensible – Easy to integrate with other Terraform modules (VPC, ELB, CloudWatch, etc.).

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Core Concepts

1. Resources Module

   • Creates and manages Auto Scaling components, including:
     • Auto Scaling Groups (ASG)
     • Launch Configurations
     • Scaling Policies
     • Lifecycle Hooks
     • Scheduled Actions
     • Notifications

2. Data Module

   • Fetches information about existing Auto Scaling resources.
   • Useful for referencing attributes like group names, ARNs, and capacity.

3. Separation of Concerns

   • resources/ handles ASG creation and configuration.
   • data/ is focused on reading and referencing existing ASG resources.
   • This separation ensures clarity, reusability, and modular design.

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Sample Usage

Terraform

# DEPLOY ANANTA CLOUD'S AUTO SCALING MODULE

module "autoscaling" {
  source = "github.com/anantacloud/terraform-aws-autoscaling-module/modules/resources"

  # ==========================
  # REQUIRED VARIABLES
  # ==========================
  name_prefix        = "my-asg"
  launch_config_name = "my-launch-config"
  min_size           = 1
  max_size           = 3
  desired_capacity   = 2
  vpc_zone_identifier = ["subnet-123456", "subnet-654321"]

  # ==========================
  # OPTIONAL VARIABLES
  # ==========================
  health_check_type         = "EC2"
  health_check_grace_period = 300

  tags = {
    Environment = "dev"
    Project     = "my-app"
  }
}

Terragrunt

# terragrunt.hcl

terraform {
  source = "github.com/anantacloud/terraform-aws-autoscaling-module/modules/resources"
}

inputs = {
  # ==========================
  # REQUIRED VARIABLES
  # ==========================
  name_prefix        = "my-asg"
  launch_config_name = "my-launch-config"
  min_size           = 1
  max_size           = 3
  desired_capacity   = 2
  vpc_zone_identifier = ["subnet-123456", "subnet-654321"]

  # ==========================
  # OPTIONAL VARIABLES
  # ==========================
  health_check_type         = "EC2"
  health_check_grace_period = 300

  tags = {
    Environment = "dev"
    Project     = "my-app"
  }
}

Opentofu

# Opentofu.hcl

terraform {
  source = "github.com/anantacloud/terraform-aws-autoscaling-module/modules/resources"
}

inputs = {
  # ==========================
  # REQUIRED VARIABLES
  # ==========================
  name_prefix        = "my-asg"
  launch_config_name = "my-launch-config"
  min_size           = 1
  max_size           = 3
  desired_capacity   = 2
  vpc_zone_identifier = ["subnet-123456", "subnet-654321"]

  # ==========================
  # OPTIONAL VARIABLES
  # ==========================
  health_check_type         = "EC2"
  health_check_grace_period = 300

  tags = {
    Environment = "dev"
    Project     = "my-app"
  }
}

Inputs

Required

Name	Description	Type	Example
name_prefix	Prefix for the Auto Scaling Group name	string	"my-asg"
launch_config_name	Name of the Launch Configuration	string	"my-launch-config"
min_size	Minimum number of instances in the group	number	1
max_size	Maximum number of instances in the group	number	3
desired_capacity	Desired number of instances	number	2
vpc_zone_identifier	List of subnet IDs for the Auto Scaling Group	list	["subnet-123456"]

Optional

Name	Description	Type	Default
health_check_type	Health check type for the group (EC2 or ELB)	string	"EC2"
health_check_grace_period	Time (in seconds) for grace period before checking	number	300
tags	Key-value tags to apply to Auto Scaling resources	map	{}

Outputs

Name	Description
asg_id	The ID of the Auto Scaling Group
asg_name	The name of the Auto Scaling Group
asg_arn	The ARN of the Auto Scaling Group
asg_min_size	The minimum size of the Auto Scaling Group
asg_max_size	The maximum size of the Auto Scaling Group
asg_desired_size	The desired size of the Auto Scaling Group