Why load balancing matters in AWS - See It in Action

Why Load Balancing Matters

📖 Scenario: You are setting up a simple web service on AWS. You want to make sure your website stays online and fast even if many people visit at the same time. To do this, you will create a load balancer that shares the visitors' requests across multiple servers.

🎯 Goal: Build an AWS Elastic Load Balancer configuration that distributes traffic evenly to two web servers, ensuring better availability and performance.

📋 What You'll Learn

Create two EC2 instances with a simple web server

Create an Elastic Load Balancer (ELB) that listens on port 80

Register the two EC2 instances with the ELB

Configure health checks for the ELB to monitor instance health

💡 Why This Matters

🌍 Real World

Load balancing helps websites and apps stay fast and available when many users visit at once by sharing the work across multiple servers.

💼 Career

Understanding load balancing is essential for cloud engineers and architects to design scalable and reliable cloud applications.

1

Create two EC2 instances

Create two EC2 instances named web-server-1 and web-server-2 using the Amazon Linux 2 AMI. Both instances should be in the us-east-1a availability zone.

AWS

# Your code here to create two EC2 instances named web-server-1 and web-server-2

Need a hint?

Use resource "aws_instance" to create EC2 instances and set the tags block with the Name key.

2

Create an Elastic Load Balancer

Create an AWS Elastic Load Balancer named web-elb that listens on port 80 for HTTP traffic.

AWS

resource "aws_instance" "web_server_1" {
  ami           = "ami-0c02fb55956c7d316"
  instance_type = "t2.micro"
  availability_zone = "us-east-1a"
  tags = {
    Name = "web-server-1"
  }
}

resource "aws_instance" "web_server_2" {
  ami           = "ami-0c02fb55956c7d316"
  instance_type = "t2.micro"
  availability_zone = "us-east-1a"
  tags = {
    Name = "web-server-2"
  }
}

# Your code here to create an Elastic Load Balancer named web-elb listening on port 80

Need a hint?

Use resource "aws_elb" and define a listener block with ports set to 80.

3

Register EC2 instances with the Load Balancer

Register the two EC2 instances web-server-1 and web-server-2 with the Elastic Load Balancer web-elb using the instances attribute.

AWS

resource "aws_instance" "web_server_1" {
  ami           = "ami-0c02fb55956c7d316"
  instance_type = "t2.micro"
  availability_zone = "us-east-1a"
  tags = {
    Name = "web-server-1"
  }
}

resource "aws_instance" "web_server_2" {
  ami           = "ami-0c02fb55956c7d316"
  instance_type = "t2.micro"
  availability_zone = "us-east-1a"
  tags = {
    Name = "web-server-2"
  }
}

resource "aws_elb" "web_elb" {
  name               = "web-elb"
  listener {
    instance_port     = 80
    instance_protocol = "http"
    lb_port           = 80
    lb_protocol       = "http"
  }
  availability_zones = ["us-east-1a"]

  # Your code here to register instances
}

Need a hint?

Add the instances attribute inside the ELB resource and list the instance IDs.

4

Configure health checks for the Load Balancer

Add a health_check block to the Elastic Load Balancer web-elb that checks the path / on port 80 every 30 seconds with a timeout of 5 seconds and considers an instance healthy after 2 successful checks.

AWS

resource "aws_instance" "web_server_1" {
  ami           = "ami-0c02fb55956c7d316"
  instance_type = "t2.micro"
  availability_zone = "us-east-1a"
  tags = {
    Name = "web-server-1"
  }
}

resource "aws_instance" "web_server_2" {
  ami           = "ami-0c02fb55956c7d316"
  instance_type = "t2.micro"
  availability_zone = "us-east-1a"
  tags = {
    Name = "web-server-2"
  }
}

resource "aws_elb" "web_elb" {
  name               = "web-elb"
  listener {
    instance_port     = 80
    instance_protocol = "http"
    lb_port           = 80
    lb_protocol       = "http"
  }
  availability_zones = ["us-east-1a"]
  instances          = [aws_instance.web_server_1.id, aws_instance.web_server_2.id]

  # Your code here to add health_check block
}

Need a hint?

Add a health_check block inside the ELB resource with the specified settings.