Day 68 -Scaling with Terraform

4 min readOct 16, 2023

Yesterday, we learned how to AWS S3 Bucket with Terraform. Today, we will see how to scale our infrastructure with Terraform. In today’s rapidly evolving digital landscape, where adaptability and scalability are critical factors for the success of any enterprise, the utilization of robust infrastructure management tools has become indispensable. Among these, Terraform, with its powerful and flexible infrastructure as code (IaC) approach, has emerged as a key player, enabling organizations to efficiently manage their infrastructure on various cloud platforms.

Understanding Scaling

Scaling is the process of adding or removing resources to match the changing demands of your application. As your application grows, you will need to add more resources to handle the increased load. And as the load decreases, you can remove the extra resources to save costs.

Terraform makes it easy to scale your infrastructure by providing a declarative way to define your resources. You can define the number of resources you need and Terraform will automatically create or destroy the resources as needed.

Tasks

Task 1: Create an Auto Scaling Group
Auto Scaling Groups are used to automatically add or remove EC2 instances based on the current demand. Follow these steps to create an Auto Scaling Group

In your main.tf file, add the following code to create an Auto Scaling Group:

   provider "aws" {
     region = "us-east-1"
   }

   resource "aws_vpc" "day68_vpc" {
     cidr_block = "10.0.0.0/16"

     tags = {
       Name = "day68_vpc"
     }
   }

   resource "aws_subnet" "day68_public_subnet" {
     vpc_id     = aws_vpc.day68_vpc.id
     cidr_block = "10.0.1.0/24"

     tags = {
       Name = "day68_public_subnet"
     }
   }

   resource "aws_subnet" "day68_private_subnet" {
     vpc_id     = aws_vpc.day68_vpc.id
     cidr_block = "10.0.2.0/24"

     tags = {
       Name = "day68_private_subnet"
     }
   }

   resource "aws_internet_gateway" "day68_igw" {
     vpc_id = aws_vpc.day68_vpc.id

     tags = {
       Name = "day68_igw"
     }
   }

   resource "aws_route_table" "day68_routetable" {
     vpc_id = aws_vpc.day68_vpc.id

     route {
       cidr_block = "0.0.0.0/0"
       gateway_id = aws_internet_gateway.day68_igw.id
     }

     tags = {
       Name = "day68_routetable"
     }
   }

   resource "aws_route_table_association" "public_subnet_association" {
     subnet_id      = aws_subnet.day68_public_subnet.id
     route_table_id = aws_route_table.day68_routetable.id
   }

   resource "aws_security_group" "day68_sg" {
     name_prefix = "day68_sg"
     vpc_id      = aws_vpc.day68_vpc.id

     ingress {
       from_port   = 80
       to_port     = 80
       protocol    = "tcp"
       cidr_blocks = ["0.0.0.0/0"]
     }

     ingress {
       from_port   = 443
       to_port     = 443
       protocol    = "tcp"
       cidr_blocks = ["0.0.0.0/0"]
     }

     ingress {
       from_port   = 22
       to_port     = 22
       protocol    = "tcp"
       cidr_blocks = ["0.0.0.0/0"]
     }

     egress {
       from_port        = 0
       to_port          = 0
       protocol         = "-1"
       cidr_blocks      = ["0.0.0.0/0"]
       ipv6_cidr_blocks = ["::/0"]
     }
   }

   resource "aws_launch_configuration" "web_server_asg" {
     name_prefix      = "web-server-asg"
     image_id         = "ami-053b0d53c279acc90"
     instance_type    = "t2.micro"
     security_groups  = [aws_security_group.day68_sg.id]
     associate_public_ip_address = true

     user_data = <<-EOF
                   #!/bin/bash
                   sudo apt update
                   sudo apt install -y apache2
                   sudo systemctl start apache2
                   sudo systemctl enable apache2
                   echo "<html><body><h1>Welcome to my website!</h1></body></html>" > /var/www/html/index.html
                   sudo systemctl restart apache2
                   EOF
   }

   resource "aws_autoscaling_group" "web_server_asg" {
     name                 = "web-server-asg"
     launch_configuration = aws_launch_configuration.web_server_asg.name
     min_size             = 1
     max_size             = 3
     desired_capacity     = 2
     health_check_type    = "EC2"
     vpc_zone_identifier  = [aws_subnet.day68_public_subnet.id]
   }

Run terraform apply to create the Auto Scaling Group.

terraform init
terraform plan
terraform appy

The instances have been created.

Task 2: Test Scaling
Go to the AWS Management Console and select the Auto Scaling Groups service.

Select the Auto Scaling Group you just created and click on the “Edit” button.

Increase the “Desired Capacity” to 3 and click on the “Save” button.

Wait a few minutes for the new instances to be launched.

Go to the EC2 Instances service and verify that the new instances have been launched.

Decrease the “Desired Capacity” to 1 and wait a few minutes for the extra instances to be terminated.

Go to the EC2 Instances service and verify that the extra instances have been terminated.

Congratulation!!! You have successfully scaled your infrastructure with Terraform.

Day 68 -Scaling with Terraform

Understanding Scaling

Tasks

Written by Radheya Zunjur

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