High-Availability VPC With Terraform

In this blog, we will show you how to create high-availability Amazon VPC with multiple VPC subnets (private and public) in different AWS availability zones.

Amazon Virtual Private Cloud (Amazon VPC) enables us to launch AWS resources into an AWS virtual network that we define. This virtual network closely resembles a traditional network that we operate in our own data center. Terraform is an open-source tool to safely and predictably create, change, and improve the infrastructure of Amazon Cloud resources.

Pre-Requisites To Creating AWS VPC Using Terraform

• We require AWS IAM API keys (access key and secret key) for creating and deleting permissions for AWS resources. 

• Terraform should be installed on the Ec2 Instance or Local Computer. If Terraform does not exist you can download and install it from here.

• GitHub command line tools should be installed.

Amazon Resources Created Using Terraform

1. AWS VPC with 10.0.0.0/16 CIDR.
2. Multiple AWS VPC Subnets which contain Amazon VPC Private Subnets, instances that are not reachable from the internet.
3. Amazon VPC Public Subnets: Instances in the public subnet would be reachable from the internet; which means traffic from the internet can hit a machine in the public subnet
4. AWS VPC Internet GateWay and attach it to AWS VPC.
5. Public and private AWS VPC Route Tables.
6. AWS VPC NAT Gateway.
7. Associating AWS VPC Subnets with VPC route tables.

Creating the Amazon VPC

In this step, we build the Amazon VPC using the Terraform script which is provided on GitHub. To get the Terraform script, clone or download from the GitHub repository provided below. It contains the complete infrastructure code to build a Amazon VPC.

Use the following command to clone or download the GitHub repository.

$ git clone https://github.com/vineet67sharma/AWS-Terraform

The GitHub repository contains the following files:

• vpc-variable.tf: The vpc-variables.tf file contains the global variables required to build Amazon VPC. The variable file contains aws_access_key , aws_secret_key , aws_region , availability_zone1 , and  availability_zone2 . We can change the variable values according your requirement and values.

• vpc-main.tf: The vpc-main.tf contains the complete code which is required to build the highly available Amazon VPC. The Terraform code launches the following resources in an Amazon account: Amazon VPC, subnets, Internet Gateway, route tables, and association route tables with route table and enabled route rules.

• aws.tf: The aws.tf is the provider's configuration file. It contains the AWS API keys to communicate with AWS API to provision the resources.

• terraform.tfvars: The Terraform.tfvars is the default name for the variable input file in Terraform.
  Terraform reads the input values from the file. We need to place or replace the AWS API Key in the file.

replace the keys

Build Amazon VPC Infrastructure

1. To initialize the working directory containing Terraform configuration files.  $ terraform init is the first command that should be run after writing a new Terraform configuration.

2. The  $terraform plan   command is used to create an execution plan. It displays the resources which are its provisions.

3. The terraform apply   command is used to apply the changes required to reach the desired state of the configuration.

#terraform apply -var-file terraform.tfvars

VPC

Subnets

Destroy The Amazon VPC Infrastructure

The terraform destroy   command is used to destroy the Terraform-managed infrastructure. Run the following command to delete the Amazon VPC which is created above. 

# terraform destroy -var-file terraform.tfvars 

The .tfstate and .tfstate.backup holds the last-known state of the infrastructure. We defined the state of an infrastructure in a group of files, bought it all up in a single command, and can track future changes with state files.