Purpose

CMS Application - Terraform Infrastructure

Pre-requisite

   1. We should have AWS access key and secret key to run this terraform code( Configure using aws cli manually or set it at ~/.aws/credentials)
   2. AWS CLI and Terraform(v12.0.0) installed on your laptop
   3. VPC, 2 Subnets,Routing Table, Security Groups,KeyPairs,S3 bucket (tfstate) ,DynamoDB(tfstate lock) created already.
   

To develop the infrastructure code for CMS Application.

Wordpress is chosen as an example for this demonstration

Usage

   Clone the repo locally into your system prefarably into XXX direcoty in c drive and make sure you have all pre-requisites setup.

Execute

Dev Environment:

     terraform init -backend=true -backend-config="bucket=cms-venkat-tfstate" -backend-config="key=cmsdeploy.tfstate"-backend-config="dynamodb_table=cms-tf-lock" --var-file="XXX\env\dev.tfvars"
     terraform plan --var-file="XXXX\env\dev.tfvars"
     terraform apply --var-file="XXXX\env\dev.tfvars"

Test Environment:
     terraform init -backend=true -backend-config="bucket=cms-venkat-tfstate" -backend-config="key=cmstst.tfstate"-backend-config="dynamodb_table=cms-tf-lock" --var-file="XXX\env\tst.tfvars"
     terraform plan --var-file="XXXX\env\tst.tfvars"
     terraform apply --var-file="XXXX\env\tst.tfvars"

The CMS must be backed by a relational database.

  1. RDS Mysql is considered for relational database and this code is defined in modules/rds folder main.tf file. 
  2. The values for the variables defined in the main.tf are declared and  initialized in modules/rds/ variables.tf file. 
  3. The DB endpoint is captured in output.tf defined in modules/rds folder.

Scalability and fault tolerance should be an important consideration of your design.

  1.Implemented AWS Autoscaling group to ensure the application is scalable - Scheduled scaling or metric based.
  2.Tried to implement Blue-Green Deployment model with basic application health checks from HA/Fault Tolerence perspective.

Reusability of the terraform module should be part of the design.

  1. Terraform Modularisation allows us to separate our Terraform files into manageable groups. There are various benefits to this such as to better organised file structure, and the ability to focus Terraform apply to a reduced scope. 
  2. In this demonstration we can see 3 modules present under modules folder. 

Provide a testing strategy for the terraform module.

  Please refer Terraform-Compliance repo for the detailed explanation as i created separate repo for this.