Template for ALB

README.md

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+# Terraform Lab
+
+Provisioning scripts for personal learning. 
+
+References
+ - [gruntwork](https://blog.gruntwork.io/an-introduction-to-terraform-f17df9c6d180)

aws_alb/main.tf

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+terraform {
+  required_version = ">= 1.0.0, < 2.0.0"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "~> 4.0"
+    }
+  }
+}
+
+provider "aws" {
+  profile = "superuser"
+  region  = "ap-southeast-2"
+}
+
+data "aws_ami" "aws_linux_ami" {
+  most_recent = true
+  owners      = ["amazon"]
+  filter {
+    name   = "name"
+    values = ["al*-ami-*-x86_64*"]
+  }
+}
+
+data "aws_vpc" "default" {
+  default = true
+}
+
+data "aws_subnets" "default" {
+  filter {
+    name   = "vpc-id"
+    values = [data.aws_vpc.default.id]
+  }
+}
+
+resource "aws_launch_configuration" "server_ami" {
+  image_id        = data.aws_ami.aws_linux_ami.id
+  instance_type   = "t2.micro"
+  security_groups = [ aws_security_group.server-sg.id ]
+  key_name        = "debin"
+
+  user_data = <<-EOF
+                #!/bin/bash
+                su -
+                sudo yum update -y
+                sudo yum install -y httpd.x86_64
+
+                echo  "Hello, World  " > /var/www/html/index.html
+                sudo systemctl start httpd.service
+                sudo systemctl enable httpd.service
+                EOF
+
+  lifecycle {
+    create_before_destroy = true
+  }
+}
+
+resource "aws_autoscaling_group" "server_group" {
+  min_size             = 2
+  max_size             = 10
+  launch_configuration = aws_launch_configuration.server_ami.name
+  vpc_zone_identifier  = data.aws_subnets.default.ids
+  target_group_arns    = [aws_lb_target_group.target_group.arn]
+  health_check_type    = "ELB"
+
+  tag {
+    key                 = "Name"
+    value               = "ASEC2"
+    propagate_at_launch = true
+  }
+}
+
+resource "aws_security_group" "server-sg" {
+  name = "alb_sec_group"
+
+  ingress {
+    description      = "TLS from VPC"
+    from_port        = var.server_port
+    to_port          = var.server_port
+    protocol         = "tcp"
+    cidr_blocks      = ["0.0.0.0/0"]
+    ipv6_cidr_blocks = ["::/0"]
+  }
+  egress {
+    description      = "all"
+    from_port        = 0
+    to_port          = 0
+    protocol         = "-1"
+    cidr_blocks      = ["0.0.0.0/0"]
+    ipv6_cidr_blocks = ["::/0"]
+  }
+}
+
+resource "aws_lb" "load_balancer" {
+  name               = "dummy-server-lb"
+  load_balancer_type = "application"
+  subnets            = data.aws_subnets.default.ids
+  security_groups    = [aws_security_group.alb_sg.id]
+}
+
+resource "aws_alb_listener" "http_endpoint" {
+  load_balancer_arn = aws_lb.load_balancer.arn
+  port              = 80
+  protocol          = "HTTP"
+
+  default_action {
+    type = "fixed-response"
+
+    fixed_response {
+      content_type = "text/plain"
+      message_body = "404"
+      status_code  = 404
+    }
+  }
+}
+
+resource "aws_security_group" "alb_sg" {
+  name = "autogerenated-exmaple-alb"
+  ingress {
+    from_port   = 80
+    to_port     = 80
+    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"]
+  }
+}
+
+resource "aws_lb_target_group" "target_group" {
+  name     = "aws-target-group"
+  port     = var.server_port
+  protocol = "HTTP"
+  vpc_id   = data.aws_vpc.default.id
+
+  health_check {
+    path                = "/"
+    protocol            = "HTTP"
+    matcher             = "200"
+    interval            = 15
+    timeout             = 3
+    healthy_threshold   = 2
+    unhealthy_threshold = 2
+  }
+}
+
+resource "aws_lb_listener_rule" "expose_80" {
+  listener_arn = aws_alb_listener.http_endpoint.arn
+  priority     = 100
+  condition {
+    path_pattern {
+      values = ["*"]
+    }
+  }
+  action {
+    type             = "forward"
+    target_group_arn = aws_lb_target_group.target_group.arn
+  }
+}

aws_alb/outputs.tf

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+output "url" {
+    value = aws_lb.load_balancer.dns_name
+    description = "URL linking to the alb endpoint."
+}

aws_alb/variables.tf

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+variable "server_port" {
+    type = number
+    default = 80
+}