Terraform Load Balancing Example

gistfile1.txt

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

provider "aws" {
  alias  = "us-west-2"
  region = "us-west-2"
}

# Fetch the latest Amazon Linux 2 AMI
data "aws_ami" "latest_amazon_linux" {
  provider = aws.us-east-1
  most_recent = true

  filter {
    name   = "name"
    values = ["amzn2-ami-hvm-*-x86_64-gp2"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["amazon"]
}

# Get the default VPC in us-east-1
data "aws_vpc" "default_us_east_1" {
  provider = aws.us-east-1
  default = true
}

# Get subnets in the default VPC in us-east-1
data "aws_subnet" "default_subnet_1a_us_east_1" {
  provider = aws.us-east-1
  vpc_id = data.aws_vpc.default_us_east_1.id
  availability_zone = "us-east-1a"
}

data "aws_subnet" "default_subnet_1b_us_east_1" {
  provider = aws.us-east-1
  vpc_id = data.aws_vpc.default_us_east_1.id
  availability_zone = "us-east-1b"
}

# Get the default security group in us-east-1
data "aws_security_group" "default_us_east_1" {
  provider = aws.us-east-1
  filter {
    name   = "group-name"
    values = ["default"]
  }

  vpc_id = data.aws_vpc.default_us_east_1.id
}

# Create EC2 instances in the default VPC in us-east-1
resource "aws_instance" "web1_us_east_1a" {
  provider               = aws.us-east-1
  ami                    = data.aws_ami.latest_amazon_linux.id
  instance_type          = "t2.micro"
  subnet_id              = data.aws_subnet.default_subnet_1a_us_east_1.id
  vpc_security_group_ids = [data.aws_security_group.default_us_east_1.id]

  tags = {
    Name = "web1_us_east_1a"
  }
}

resource "aws_instance" "web2_us_east_1b" {
  provider               = aws.us-east-1
  ami                    = data.aws_ami.latest_amazon_linux.id
  instance_type          = "t2.micro"
  subnet_id              = data.aws_subnet.default_subnet_1b_us_east_1.id
  vpc_security_group_ids = [data.aws_security_group.default_us_east_1.id]

  tags = {
    Name = "web2_us_east_1b"
  }
}

# Create Load Balancer in us-east-1
resource "aws_lb" "my_lb_us_east_1" {
  provider             = aws.us-east-1
  name                 = "my-lb-us-east-1"
  internal             = false
  load_balancer_type   = "application"
  security_groups      = [data.aws_security_group.default_us_east_1.id]
  subnets              = [data.aws_subnet.default_subnet_1a_us_east_1.id, data.aws_subnet.default_subnet_1b_us_east_1.id]
  enable_deletion_protection = true
  enable_cross_zone_load_balancing = true
}

resource "aws_lb_listener" "front_end_us_east_1" {
  provider            = aws.us-east-1
  load_balancer_arn   = aws_lb.my_lb_us_east_1.arn
  port                = "80"
  protocol            = "HTTP"

  default_action {
    type = "forward"
    target_group_arn = aws_lb_target_group.my_target_group_us_east_1.arn
  }
}

resource "aws_lb_target_group" "my_target_group_us_east_1" {
  provider            = aws.us-east-1
  name                = "my-target-group-us-east-1"
  port                = 80
  protocol            = "HTTP"
  vpc_id              = data.aws_vpc.default_us_east_1.id

  health_check {
    healthy_threshold   = 2
    unhealthy_threshold = 2
    timeout             = 3
    interval            = 30
    path                = "/"
    matcher             = "200"
  }
}

resource "aws_lb_target_group_attachment" "web1_us_east_1" {
  provider            = aws.us-east-1
  target_group_arn    = aws_lb_target_group.my_target_group_us_east_1.arn
  target_id           = aws_instance.web1_us_east_1a.id
  port                = 80
}

resource "aws_lb_target_group_attachment" "web2_us_east_1" {
  provider            = aws.us-east-1
  target_group_arn    = aws_lb_target_group.my_target_group_us_east_1.arn
  target_id           = aws_instance.web2_us_east_1b.id
  port                = 80
}

# Repeat for us-west-2 region
data "aws_ami" "latest_amazon_linux_us_west_2" {
  provider = aws.us-west-2
  most_recent = true

  filter {
    name   = "name"
    values = ["amzn2-ami-hvm-*-x86_64-gp2"]
  }

  filter {
    name   = "virtualization-type"
    values = ["hvm"]
  }

  owners = ["amazon"]
}

# Get the default VPC in us-west-2
data "aws_vpc" "default_us_west_2" {
  provider = aws.us-west-2
  default = true
}

# Get subnets in the default VPC in us-west-2
data "aws_subnet" "default_subnet_1a_us_west_2" {
  provider = aws.us-west-2
  vpc_id = data.aws_vpc.default_us_west_2.id
  availability_zone = "us-west-2a"
}

data "aws_subnet" "default_subnet_1b_us_west_2" {
  provider = aws.us-west-2
  vpc_id = data.aws_vpc.default_us_west_2.id
  availability_zone = "us-west-2b"
}

# Get the default security group in us-west-2
data "aws_security_group" "default_us_west_2" {
  provider = aws.us-west-2
  filter {
    name   = "group-name"
    values = ["default"]
  }

  vpc_id = data.aws_vpc.default_us_west_2.id
}

# Create EC2 instances in the default VPC in us-west-2
resource "aws_instance" "web1_us_west_2a" {
  provider               = aws.us-west-2
  ami                    = data.aws_ami.latest_amazon_linux_us_west_2.id
  instance_type          = "t2.micro"
  subnet_id              = data.aws_subnet.default_subnet_1a_us_west_2.id
  vpc_security_group_ids = [data.aws_security_group.default_us_west_2.id]

  tags = {
    Name = "web1_us_west_2a"
  }
}

resource "aws_instance" "web2_us_west_2b" {
  provider               = aws.us-west-2
  ami                    = data.aws_ami.latest_amazon_linux_us_west_2.id
  instance_type          = "t2.micro"
  subnet_id              = data.aws_subnet.default_subnet_1b_us_west_2.id
  vpc_security_group_ids = [data.aws_security_group.default_us_west_2.id]

  tags = {
    Name = "web2_us_west_2b"
  }
}

# Create Load Balancer in us-west-2
resource "aws_lb" "my_lb_us_west_2" {
  provider             = aws.us-west-2
  name                 = "my-lb-us-west-2"
  internal             = false
  load_balancer_type   = "application"
  security_groups      = [data.aws_security_group.default_us_west_2.id]
  subnets              = [data.aws_subnet.default_subnet_1a_us_west_2.id, data.aws_subnet.default_subnet_1b_us_west_2.id]
  enable_deletion_protection = true
  enable_cross_zone_load_balancing = true
}

resource "aws_lb_listener" "front_end_us_west_2" {
  provider            = aws.us-west-2
  load_balancer_arn   = aws_lb.my_lb_us_west_2.arn
  port                = "80"
  protocol            = "HTTP"

  default_action {
    type = "forward"
    target_group_arn = aws_lb_target_group.my_target_group_us_west_2.arn
  }
}

resource "aws_lb_target_group" "my_target_group_us_west_2" {
  provider            = aws.us-west-2
  name                = "my-target-group-us-west-2"
  port                = 80
  protocol            = "HTTP"
  vpc_id              = data.aws_vpc.default_us_west_2.id

  health_check {
    healthy_threshold   = 2
    unhealthy_threshold = 2
    timeout             = 3
    interval            = 30
    path                = "/"
    matcher             = "200"
  }
}

resource "aws_lb_target_group_attachment" "web1_us_west_2" {
  provider            = aws.us-west-2
  target_group_arn    = aws_lb_target_group.my_target_group_us_west_2.arn
  target_id           = aws_instance.web1_us_west_2a.id
  port                = 80
}

resource "aws_lb_target_group_attachment" "web2_us_west_2" {
  provider            = aws.us-west-2
  target_group_arn    = aws_lb_target_group.my_target_group_us_west_2.arn
  target_id           = aws_instance.web2_us_west_2b.id
  port                = 80
}