Yesterday, we learned how to AWS S3 Bucket with Terraform. Today, we will see how to scale our infrastructure with Terraform.

🔶 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.

🔶 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 Nilesh Sahare!</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.

🔶 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.

Congratulations🎊🎉 We have successfully scaled your infrastructure with Terraform

Happy Learning :)

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Day 68 Task: Scaling with Terraform

Table of contents

🔶 Understanding Scaling

🔶 Task 1: Create an Auto Scaling Group

🔶 Task 2: Test Scaling

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Nilesh Sahare

Nilesh Sahare