Automate a dynamic Infrastructure over AWS using Terraform

• What is Terraform :

Terraform is an open-source infrastructure as code software tool that enables you to safely and predictably create, change, and improve infrastructure. Users define and provide data center infrastructure using a declarative configuration language known as HashiCorp Configuration Language, or optionally JSON.

• Deliver Infrastructure As Code :

1. WRITE - Write infrastructure as code using declarative configuration files. HashiCorp Configuration Language (HCL) allows for concise descriptions of resources using blocks, arguments, and expressions.
2. PLAN - Run terraform plan to check whether the execution plan for a configuration matches your expectations before provisioning or changing infrastructure.
3. APPLY - Apply changes to hundreds of cloud providers with terraform apply to reach the desired state of the configuration.

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• The following resources are being used:

VPC , Security Group , Internet Gateway , Subnets , Route Table and S3

STEP 1 : Create a provider.tf file for providing the region as well as the access and secret key of your AWS a/c or you can also use your "default" profile. I also created a var.tf file for storing all the variables used in the code at one single place.

The var.tf file :

variable "aws_region" {
    default = "ap-south-1"
}


variable "vpc_cidr" {
    default = "10.0.0.0/16"
}


variable "subnet_cidr" {
    default = [ "10.0.1.0/24" , "10.0.2.0/24"]
    type = list
}


variable "azs" {
    type = list
    default = [ "ap-south-1a" , "ap-south-1b" , "ap-south-1c"]
}


variable "ami" {
    default = "ami-010aff33ed5991201"
}


variable "ec2_type" {
    default = "t2.micro"
}

The provider.tf file: Terraform's resources are implemented by provider plugins. The Terraform Registry is the main directory of publicly available Terraform providers.

provider "aws" {
	    region = var.aws_region    
	    profile = "default"

	
}

STEP 2 : Now create a file for the setup of all the resources needed, which in my case is named as vpc.tf

Create a VPC : Amazon Virtual Private Cloud (Amazon VPC) enables you to launch AWS resources into a virtual network that you've defined. Amazon VPC is the networking layer for Amazon EC2.

#Creating a VPC
	resource "aws_vpc" "my_vpc" {
	    cidr_block = var.vpc_cidr
	

	    tags = {
	       Name = "My VPC"
	}

	}
}

Create a Security group linked to this VPC : A security group acts as a virtual firewall for your instance to control inbound and outbound traffic. When you launch an instance in a VPC, you can assign up to five security groups to the instance.

#Creating a Security Group 
	resource "aws_default_security_group" "sg" {
	  vpc_id = aws_vpc.my_vpc.id
	

	  ingress {
	    protocol  = -1
	    self      = true
	    from_port = 0
	    to_port   = 0
	  }
	

	  egress {
	    from_port   = 0
	    to_port     = 0
	    protocol    = "-1"
	  }
	

	  tags = {
	    Name = "MY SG"
	  }

	
}

Create an Internet Gateway : An internet gateway is a horizontally scaled, redundant, and highly available VPC component that allows communication between your VPC and the internet.

#Creating IN Gateway
	resource "aws_internet_gateway" "gw" {
	    vpc_id = aws_vpc.my_vpc.id
	

	    tags = {
	       Name = "My gw"
	}

	}
}

Creating the Subnets : Since I need to launch two subnets in the above created VPC, so to make it more dynamic I used Terraform loops and function for this purpose.

#Creating Subnets
	resource "aws_subnet" "my_subnet" {
	  count = length(var.subnet_cidr)
	  vpc_id     = aws_vpc.my_vpc.id
	  cidr_block = element(var.subnet_cidr,count.index)
	  availability_zone= element(var.azs,count.index)
	  map_public_ip_on_launch = true
	

	  tags = {
	      Name = "Subnet-${count.index+1}"
	  }

	
}

Create a Route Table : A route table contains a set of rules, called routes, that are used to determine where network traffic from your subnet or gateway is directed.

#Creating Route tables
	resource "aws_route_table" "rt" {
	  vpc_id = aws_vpc.my_vpc.id
	

	  route {
	    cidr_block = "0.0.0.0/0"
	    gateway_id = aws_internet_gateway.gw.id
	  }
	

	  tags = {
	        Name = "RT"
	    }

	
}

Association of the Route Table : The association between a route table and a subnet, internet gateway, or virtual private gateway.

#Associating RT
	resource "aws_route_table_association" "rt_ass" {
	  count = length(var.subnet_cidr)
	  subnet_id      = element(aws_subnet.my_subnet.*.id,count.index)
	  route_table_id = aws_route_table.rt.id

	
}

STEP 3 : Now, I created a S3 bucket for uploading my student login form created in my local system.

S3 bucket : Amazon S3 or Amazon Simple Storage Service is a service offered by Amazon Web Services that provides object storage through a web service interface.

#Crearing a bucket
	resource "aws_s3_bucket" "bucket" {
	  bucket = "s3-website-test.myhashicorp.com"
	

	  website {
	    index_document = "myweb.html"
	   }
	}
	

	#Uploading files
	resource "aws_s3_bucket_object" "object" {
	  bucket = "s3-website-test.myhashicorp.com"
	  key    = "webpage.html"
	  source = "C:/Users/sujag/Desktop/Terraform/dynamic_iaas/web.html"

	
}

STEP 4 : Now, apply the code for the whole setup

terraform init
terraform plan
terraform apply --auto-approve

Results :

Also , we can destroy the whole infrastructure in one single click

terraform destroy

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THANK YOU !