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Create an Instance with an Elastic IP Attached using Terraform

charlesuneze

Charles Uneze

Posted on March 6, 2023

Create an Instance with an Elastic IP Attached using Terraform

On my journey to explore the Kubernetes networking ecosystem, I decided to take my first step by completing the AWS Networking course outline using Terraform. I am attempting to gain an understanding of how things work at this layer.

Image description

Laying the Ground Work for My Code

The first thing I did was to install Terraform using this tutorial.

Defining the Backend for Storing Infrastructure Information

The next thing I did was to create a "Terraform.tf" file so I can set up the backend where all the information about this infrastructure will be stored. The information is mapped to the real infrastructure on AWS. I use a local backend, meaning the information is stored on my computer. This information is in JSON format.



terraform {
    backend "local" {
      path = ""
    }

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.0"
    }
  }
}
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The above code in this file specifies that I am using a local backend, and also that I am using an “AWS provider.” The provider is a plugin for interacting with the AWS APIs so the infrastructure can be built.

Specifying the Cloud Provider

Next I created a "main.tf" file where I will specify the cloud provider and also the architecture as code.



# Configure the AWS Provider
provider "aws" {
  region = "us-west-2"
  access_key = ""
  secret_key = ""
}
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Algorithm of the Architecture

  1. Create a VPC
  2. Specify the default NACL
  3. Specify the default security group
  4. Create an Internet Gateway
  5. Specify the default route table, and add a new route to the Internet Gateway.
  6. Create a subnet
  7. Create an instance
  8. Create an elastic IP address

Create a VPC

VPC = 10.0.0.0/16



# Create VPC
resource "aws_vpc" "VPC_A" {
  cidr_block       = "10.0.0.0/16"
  instance_tenancy = "default"

  tags = {
    name = "VPC_A"
  }
}
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When a VPC is created, AWS uses an overlay network to offer multi-tenancy for implementation. I wrote some words about this on my substack.

Specify the default NACL 



# Specify the default NACL, regardless if the VPC creates it on default
resource "aws_default_network_acl" "Default_VPC_A_NACL" {
  default_network_acl_id = aws_vpc.VPC_A.default_network_acl_id

  ingress {
    protocol   = -1
    rule_no    = 100
    action     = "allow"
    cidr_block = "0.0.0.0/0"
    from_port  = 0
    to_port    = 0
  }

  egress {
    protocol   = -1
    rule_no    = 100
    action     = "allow"
    cidr_block = "0.0.0.0/0"
    from_port  = 0
    to_port    = 0
  }

  tags = {
    "name" = "Default_VPC_A_NACL"
  }
}
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Specify the default security group 



# Specify the default SG, regardless if the VPC creates it on default
resource "aws_default_security_group" "Default_VPC_A_SG" {
  vpc_id = aws_vpc.VPC_A.id

  ingress {
    protocol  = -1
    from_port = 0
    to_port   = 0
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = -1
    cidr_blocks = ["0.0.0.0/0"]
  }

  tags = {
    "name" = "Default_VPC_A_SG"
  }
}
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Create an Internet Gateway 



# Create the Internet Gateway
resource "aws_internet_gateway" "VPC_A_IGW" {
  vpc_id = aws_vpc.VPC_A.id

  tags = {
    name = "VPC_A_IGW"
  }
}
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Specify the default route table, and add a new route to the Internet Gateway 



# Create the default route table
resource "aws_default_route_table" "VPC_A_Default_RT" {
  default_route_table_id = aws_vpc.VPC_A.default_route_table_id

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

  tags = {
    name = "VPC_A_Default_RT"
  }
}
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Create a subnet 



# Create Subnet
resource "aws_subnet" "VPC_A_Subnet_A" {
  vpc_id                  = aws_vpc.VPC_A.id
  cidr_block              = "10.0.0.0/24"
  availability_zone       = "us-west-2a"

  tags = {
    name = "VPC_A_Subnet_A"
  }
}
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Create an Instance 



# Create AWS instance
resource "aws_instance" "VPC_A_Subnet_A_AWS_Linux" {
  ami               = "ami-0b029b1931b347543"
  instance_type     = "t2.micro"
  tenancy           = "default"
  availability_zone = "us-west-2a"
  subnet_id = aws_subnet.VPC_A_Subnet_A.id

  tags = {
    name = "VPC_A_Subnet_A_AWS_Linux"
  }
}
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Create an elastic IP address 



# Create an Elastic IP
resource "aws_eip" "VPC_A_EIP" {
  instance = aws_instance.VPC_A_Subnet_A_AWS_Linux.id
  vpc      = true
  tags = {
    name = "VPC_A_EIP"
  }
}

# Associate the Elastic IP to the instance
resource "aws_eip_association" "VPC_A_EIP-Association" {
  instance_id   = aws_instance.VPC_A_Subnet_A_AWS_Linux.id
  allocation_id = aws_eip.VPC_A_EIP.id
}
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After applying the configuration, check for the public IP address of the script via the command below
terraform state show aws_eip.VPC_A_EIP
Then do a ping to the public IP address, make sure it is successful.

Do make a comment if you experience any issue in the code or article.

Follow my AWS Advanced Networking Journey on Github

AWS Advanced Networking
https://github.com/Its-All-About-the-Journey/AWS-Advanced-Networking

💖 💪 🙅 🚩
charlesuneze
Charles Uneze

Posted on March 6, 2023

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