Create Multiple EC2 instance with Nginx Role using Terraform

Description: Here I have explained, How to create multiple EC2 instance with Nginx Role using Terraform.

Prerequisites:

• SSH Key in AWS
• IAM user with EC2 Full access
• Default VPC in EC2 instance

First creating provider file provider.tf for region access and secret keys

provider "aws" {
  region     = "us-east-1"
  access_key = "XXXXXXXXXXXXXXXXXXX"
  secret_key = "XXXXXXXXXXXXXXXXXXXXXXXXX"
}

Define Variables like port, image_id and instance_type in variable file variable.tf  

variable ports {
    type = list(number)
    }

variable image_id {
    type = string
}

variable "instance_type" {
    type = string
}

Variable define in terraform.tfvars

ports=[22,80,443]
image_id="ami-04505e74c0741db8d"
instance_type="t2.micro"

Define Security group rule in Securitygroup.tf. For inbound port, I have used dynamic block for multiple port numbers define in terraform.tfvars file  "ports=[22,80,443]"

### Creating Security Group ###
resource "aws_security_group" "terrainstance" {
  name        = "Web_SG"
  description = "Security Group for Web"
  egress {
      from_port = 0
      to_port = 0
      protocol = "-1"
      cidr_blocks = ["0.0.0.0/0"]
  }

  dynamic "ingress" {
    for_each = var.ports
    iterator = port
    content {
      description = "Port for SG"
      from_port   = port.value
      to_port     = port.value
      protocol    = "tcp"
      cidr_blocks = ["0.0.0.0/0"]
    }
}
}

Shell script to install Nginx and start the service

#!/bin/bash
apt update 
apt-get install nginx -y
echo "this is techserverglobal" > /var/www/html/index.nginx-debian.html
systemctl start nginx
systemctl enable nginx

Instance.tf file for launch instance by using all the above variable. Here I define 3 count for 3 instance and name of the instance will be like "NginxWeb-0, NginxWeb-1 and NginxWeb-2"

resource "aws_instance" "terrainstance" {
  ami             = "${var.image_id}"
  instance_type   = "${var.instance_type}"
  count = 3
  key_name        = "terraform-key"
  security_groups = ["${aws_security_group.terrainstance.name}"]
  tags = {
    Name = "NginxWeb-${count.index}"
  }
  user_data = "${file("nginx.sh")}"
}

Plan and Apply terraform project

Verify in AWS console