3-tier application Demo

Technical Overview

Welcome to the technical documentation for your inaugural AWS project! In this phase, you will be orchestrating a 3-tier application within your internal AWS Organization using Terraform as the Infrastructure as Code (IaC) tool. The architecture comprises 2 frontend machines, 2 backend machines, and 2 databases, meticulously configured in a multi-AZ (Availability Zone) setup. The application's gateway is facilitated through an Application Load Balancer (ALB) residing in a public subnet, while all machines, including frontends and backends, are strategically positioned in private subnets. An additional internal Load Balancer (LB) will be integral for secure communication between the tiers.

Project Components

Frontend

• Node.js application running on 2 machines.
• Deployed using Auto Scaling Groups (ASG) for scalability.
• Utilizes custom Amazon Machine Images (AMIs).
• Exposed on ports 3000.
• Machines situated in private subnets.

Backend

• Python Flask application running on 2 machines.
• Deployed using Auto Scaling Groups (ASG) for scalability.
• Utilizes custom Amazon Machine Images (AMIs).
• Operating on ports 5000.
• Machines positioned in private subnets.

Databases

• 2 databases deployed in a multi-AZ configuration.
• Utilizes one master and one replica instance.
• Specific database configurations are to be customized.

Load Balancers

• External ALB for public access.
• Internal LB to manage communication between tiers.

Setup Instructions

Follow the precise steps below to set up the project:

1. Clone the repository:

   git clone https://github.com/orasraf12/3-tier-application-Demo.git
   cd 3-tier-application-Demo/terraform
   

2. Initialize Terraform:

   terraform init 
   

3. Review and modify variables in terraform.tfvars file.

4. Deploy the infrastructure:

   terraform apply 
   # Enter your database password when prompted
   
   

Accessing the Application

Access the application through the public URL provided by the ALB. Access the EC2 machines using Session Manager.

Providers

Name	Version
aws	5.38.0

Modules

Name	Source	Version
backend_asg	terraform-aws-modules/autoscaling/aws	n/a
frontend_asg	terraform-aws-modules/autoscaling/aws	n/a
vpc	terraform-aws-modules/vpc/aws	~> 5.0

Resources

Name	Type
aws_autoscaling_attachment.asg_to_alb_backend	resource
aws_autoscaling_attachment.asg_to_alb_frontend	resource
aws_db_instance.mysql-rds	resource
aws_db_instance.replica-mysql-rds	resource
aws_db_subnet_group.db_subnet_group	resource
aws_lb.application-lb_frontend	resource
aws_lb.application_lb_backend	resource
aws_lb_listener.alb-listener	resource
aws_lb_listener.alb_listener_backend	resource
aws_lb_target_group.target_group_backend	resource
aws_lb_target_group.target_group_fronted	resource
aws_route53_record.backend	resource
aws_route53_record.database	resource
aws_route53_record.frontend	resource
aws_route53_zone.private	resource
aws_security_group.backend-server	resource
aws_security_group.lb_sg	resource
aws_security_group.rds_sg	resource

Inputs

Name	Description	Type	Default	Required
aws_lb_listener_type	the type of the aws_lb_listener	string	"forward"	no
azs	A list of availability zones names or ids in the region	list(string)	[ "eu-west-2a", "eu-west-2b" ]	no
backend_ami	n/a	string	"ami-04e1ec573bbbafba8"	no
backend_asg	n/a	string	"backend-asg"	no
backend_asg_desired_capacity	n/a	number	2	no
backend_asg_max_size	n/a	number	4	no
backend_asg_min_szie	n/a	number	2	no
backend_asg_wait_for_capacity_timeout	n/a	number	0	no
backend_instance_type	n/a	string	"t3.micro"	no
backend_name	name fo the backend	string	"backend"	no
cidr	VPC CIDR Block	string	"10.0.0.0/16"	no
create_database_subnet_group	VPC Create Database Subnet Group, Controls if database subnet group should be created	bool	true	no
create_database_subnet_route_table	VPC Create Database Subnet Route Table, Controls if separate route table for database should be created	bool	true	no
database_subnets	A list of database subnets inside the VPC	list(string)	[ "10.0.151.0/24", "10.0.152.0/24" ]	no
db_engine	type of the db engine for example mysql or postgress etc...	string	"mysql"	no
db_engine_version	version of the db engine	string	"5.7"	no
db_instance_type	the db instance type	string	"db.t3.micro"	no
db_name	database name	string	"backend"	no
db_pass	password of the database live it empty and enter when you create	string	n/a	yes
db_user	user name for the data base	string	"root"	no
enable_nat_gateway	Should be true if you want to provision NAT Gateways for each of your private networks	bool	true	no
frontend_ami	n/a	string	"ami-0e6c17d28dc6c4208"	no
frontend_asg_desired_capacity	n/a	number	2	no
frontend_asg_max_size	n/a	number	4	no
frontend_asg_min_szie	n/a	number	2	no
frontend_asg_name	frontend vars	string	"frontend-asg"	no
frontend_asg_wait_for_capacity_timeout	n/a	number	0	no
frontend_instance_type	n/a	string	"t3.micro"	no
frontend_name	The name fo the frontend env for DNS	string	"frontend"	no
ip_address_type	the type of the ip address ipv4 or ipv6	string	"ipv4"	no
load_balancer_internal	the ttype of LB application, nework etc...	bool	false	no
load_balancer_type	the ttype of LB application, nework etc...	string	"application"	no
port_backend	port number of the backend app	number	5000	no
port_database	port number of the database app	number	3306	no
port_frontend	port number of the frontend app	number	3000	no
port_http	port number of the database app	number	80	no
private_subnets	A list of private subnets inside the VPC	list(string)	[ "10.0.1.0/24", "10.0.2.0/24" ]	no
protocol_http	http protocol for sg and helthchecks	string	"HTTP"	no
protocol_tcp	tcp protocol name for sg and helthchecks	string	"tcp"	no
public_subnets	A list of public subnets inside the VPC	list(string)	[ "10.0.101.0/24", "10.0.102.0/24" ]	no
region	Region in which AWS Resources to be created	string	"eu-west-2"	no
sg_cidr	all to ip range	list(string)	[ "0.0.0.0/0" ]	no
single_nat_gateway	Should be true if you want to provision a single shared NAT Gateway across all of your private networks	bool	true	no
tags	############################################## Tags #####################################	map(string)	{ "Created By": "orasraf@terasky.com", "Env": "stage", "Purpose": "learning", "terraform": "true" }	no
target_type	The type for target group	string	"instance"	no
vpc_name	VPC Name	string	"vpc"	no

Outputs

Name	Description
azs	A list of availability zones specified as argument to this module
nat_public_ips	List of public Elastic IPs created for AWS NAT Gateway
private_subnets	A list of private subnets inside the VPC
public_subnets	A list of public subnets inside the VPC
vpc_cidr_block	The CIDR block of the VPC
vpc_id	The ID of the VPC