Automating Cloud Infrastructure with Terraform: A Step by Step Guide🚀

#provider

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

# Configure the AWS Provider
provider "aws" {
  region = "us-west-1"
}



#EC2

resource "aws_instance" "app_server" {
  ami           = "ami-0ce2cb35386fce9"
  instance_type = "t2.micro"
  count = 1
  availability_zone = "us-west-1a"
  subnet_id     = aws_subnet.mark_public_subnet_1.id # specify the subnet ID where instances will be launched
  key_name      = "mark_key" # specify the SSH key pair name
  security_groups = [aws_security_group.allow_web.id] # specify the security group(s) for the instance(s)

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



#security

resource "aws_security_group" "allow_web" {
  name        = "allow_web"
  description = "Allow TLS inbound traffic"
  vpc_id = aws_vpc.mark_vpc.id
  // Ingress rules (inbound traffic)
  ingress {
    description = "HTTP"
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"] // allow traffic from anywhere
  }

  ingress {
    description = "SSH"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"] // allow SSH from anywhere
  }

  ingress {
    description = "SSH"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["171.50.247.221/32"] // allow SSH from myIP
  }
  // Egress rules (outbound traffic)
  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1" // all protocols
    cidr_blocks = ["0.0.0.0/0"] // allow traffic to anywhere
  }
}



#vpc

resource "aws_vpc" "mark_vpc" {
  cidr_block = "55.55.0.0/16" # specify the CIDR block for your VPC
  enable_dns_support = true
  enable_dns_hostnames = true

  tags = {
    Name = "mark-vpc"
  }
}



#subnets

resource "aws_subnet" "mark_public_subnet_1" {
  vpc_id            = aws_vpc.mark_vpc.id # specify the ID of the existing VPC
  cidr_block        = "55.55.1.0/24"  # specify the CIDR block for the subnet
  availability_zone = "us-west-1a"   # specify the availability zone

  map_public_ip_on_launch = true  # enable auto-assign public IP addresses

  tags = {
    Name = "mark_public-subnet-1"
  }
}

resource "aws_subnet" "mark_public_subnet_2" {
  vpc_id            = aws_vpc.mark_vpc.id # specify the ID of the existing VPC
  cidr_block        = "55.55.2.0/24"  # specify the CIDR block for the subnet
  availability_zone = "us-west-1b"   # specify the availability zone

  map_public_ip_on_launch = true  # enable auto-assign public IP addresses

  tags = {
    Name = "mark_public-subnet-2"
  }
}

resource "aws_subnet" "mark_private_subnet_1" {
  vpc_id            = aws_vpc.mark_vpc.id # specify the ID of the existing VPC
  cidr_block        = "55.55.3.0/24"  # specify the CIDR block for the subnet
  availability_zone = "us-west-1a"   # specify the availability zone

  tags = {
    Name = "mark_private-subnet-1"
  }
}

resource "aws_subnet" "mark_private_subnet_2" {
  vpc_id            = aws_vpc.mark_vpc.id # specify the ID of the existing VPC
  cidr_block        = "55.55.4.0/24"  # specify the CIDR block for the subnet
  availability_zone = "us-west-1b"   # specify the availability zone

  tags = {
    Name = "mark_private-subnet-2"
  }
}



#routetable

resource "aws_route_table" "public_route_table_1" {
  vpc_id = aws_vpc.mark_vpc.id # reference to the VPC ID

  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.mark-igw.id # reference to the Internet Gateway ID
  }

  tags = {
    Name = "MARK-rtb-public1-us-west-1a"
  }
}

resource "aws_route_table_association" "rts-mark-public1" {
  subnet_id = aws_subnet.mark_public_subnet_1.id
  route_table_id = aws_route_table.public_route_table_1.id
}

resource "aws_route_table" "public_route_table_2" {
  vpc_id = aws_vpc.mark_vpc.id # reference to the VPC ID

  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.mark-igw.id # reference to the Internet Gateway ID
  }

  tags = {
    Name = "MARK-rtb-public2-us-west-1b"
  }
}

resource "aws_route_table_association" "rts-mark-public2" {
  subnet_id = aws_subnet.mark_public_subnet_2.id
  route_table_id = aws_route_table.public_route_table_2.id
}

resource "aws_route_table" "private_route_table_1" {
  vpc_id = aws_vpc.mark_vpc.id # reference to the VPC ID

  tags = {
    Name = "MARK-rtb-private1-us-west-1a"
  }
}

resource "aws_route_table_association" "rts-mark-private1" {
  subnet_id = aws_subnet.mark_private_subnet_1.id
  route_table_id = aws_route_table.private_route_table_1.id
  }

resource "aws_route_table" "private_route_table_2" {
  vpc_id = aws_vpc.mark_vpc.id # reference to the VPC ID

  tags = {
    Name = "MARK-rtb-private2-us-west-1b"
  }
}

resource "aws_route_table_association" "rts-mark-private2" {
  subnet_id = aws_subnet.mark_private_subnet_2.id
  route_table_id = aws_route_table.private_route_table_2.id  
}



#internet gateway

resource "aws_internet_gateway" "mark-igw" {
  vpc_id = aws_vpc.mark_vpc.id # reference to the VPC ID
  tags = {
    Name = "mark-igw"
  }
}