Two-Tier-Application-Using-Terraform

What Is Terraform ?

Terraform is an infrastructure as code tool (IAC) that lets you build, change, and version cloud and on-prem resources safely and efficiently.

Purpose

• Create and provision resources from any cloud provider (In our situation it would be AWS).
• Integrate with other modules, that have been already created and shared on github.

Desired Architecture

Prerequisite

• Install Terraform
• AWS account (you might consider using Free Tier)
• Install AWS CLI for authentication with AWS config.

Modules

• Terraform-Network-Module
• Terraform--Web-Application-Module
• Terraform-RDS-Module

Steps and Modules role

• From AWS account console, create a custom VPC and S3 bucket .
• Configure AWS CLI aws configure with access key, secret access key and region.
• In provider.tf file :
  • specify the source , region and version for the cloud provider.
  • choose S3 bucket as the backend to store terraform.tfstate file.

Each Module that was mentioned above has a certain role to achieve

Network Module do the following:

• Reference the VPC, Create 2 private and 1 public subnets.
• Create internet Gateway.
• Create route table with its association between the public subnet and internet Gateway.
• Create a subnet group of the private subnets.

APP Module do the following:

• Create a security group to allow HTTP/s traffic.
• Create EC2 instance (will be attached to the public subnet which was created in the Netwok module).
• Attach the security group to the EC2 instance.

RDS Module do the following:

• Create a security group to allow the access from the EC2's security group only.
• Create RDS instance (will be attached to the private subnet group which was created in the Netwok module).
• Attach the security group to the RDS instance.

• main.tf file contains the reference for each module( repo URL and variables )
• output.tf file in each module, allow passing values from a module to variables in another module

Project RUN

1. terraform init intialize the project with all required modules and files of the cloud provider.
2. terraform plan validate all resources (dry-run technique).
3. terraform apply Create all resources (the real effect).