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!</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 init, plan and apply to create the Auto Scaling Group.
Task-02: 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🎊🎉 You have successfully scaled your infrastructure with Terraform.
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