Multi-tier Architecture on AWS

About

Build a multi-tier architecture project with various AWS services for real time environments.

• R53 - To create record sets within hosted zones.
• VPC - To create subnets, internet gateway, route tables, security groups.
• SNS - For notification services.
• ELB - For load balancing.
• ACM - For SSL certificates.
• EC2 - Instances with elastic IP and Auto Scaling group attached.
• RDS - Master database with multi - AZ configuration.

Steps :

1. Public and private subnets, IGW, NAT Gateway,etc.

VPC

Public Subnet - 1

Public Subnet - 2

Private Subnet - 1

Private Subnet - 2

Created

IGW

Attached to VPC

Private Route table for VPC


NAT Gateway with attached Elastic IP

Associate private subnets with NAT Gateway
Associate NAT gateway to Private RT

Attach private subnets to Private RT

Attach IGW to Public RT

VPC setup completed!

2. Create EC2 instance with Userdata (Bootstrapping) script.

Amazon Linux 2 -T2 micro
VPC - Komla-VPC


Create IAM role for EC2 service for S3 access

Attach it to the EC2 instance

Create SNS topic

Add subscription email

EC2 setup complete!

3. Create RDS Security Group and RDS subnet group with Private Subnets.

Create security group

Provided access to only webserver SG

Create Database
Type - MySQL
VPC - Komla-VPC
SG - Security group for incoming traffic from EC2 on port 3306.
Instance - db.t2.micro

Database created!
Create ELB

VPC - Komla-VPC

Spread across Public subnets

Create SG for load balancer

Health check parameters

Add EC2 instance


ELB created!

Apache server operating. EC2 instance healthy!

4. Launch RDS instance with Multi-AZ.

5. Install WordPress.

Latest version of WordPress requires atleast php 5.6. Amazon t2 micro comes with php 5.4 standard. To bypass this issue I installed php 7. Refer.

           sudo amazon-linux-extras install -y php7.2
           sudo service httpd restart

Installing Wordpress: Official tutorial
wget https://wordpress.org/latest.tar.gz

Extracted the downloaded package from wordpress with
tar -xzf latest.tar.gz

Moved the contents of wordpress directory to /var/www/html

cd /etc/httpd/conf
edit httpd.conf

Search for "AllowOverride None" change None to All.
It is in /var/www/html directory.
Change permissions on html directory.
chown -R apache:apache /var/www/html.

Wordpress opens on the Public IP of EC2 instance!
http://18.***.161.241/wp-admin/setup-config.php

Check whether RDS is accessible via EC2 instance.

After configuring the dbname,username, password, hostname the wordpress application is up and running on Public IP of EC2 instance on the browser!

6. Create Route53 hosted zone to map with domain.

The ELB DNS is configured as an A record for the domain name wordpress.komlalebu.com.

7. Create AMI for EC2.

8. Create ELB.

The EC2 instances are now accessed with the ELB DNS.

9. Create launch configuration from AMI.

Running two desired instances

10. Create ASG for launch configuration.

VPC - Komla-VPC
Subnets - Public subnets
ELB - Komla-ELB
Desired - 2 instances
Minimum - 1 instances
Maximun - 2 instances

Scaling policy

11. Health Check and fault tolerance.

Terminated all instances created by Auto Scaling for testing.

Health check failed and a new instance was created from AMI with ASG.

Notification received in mail whenever instances are terminated or launched.


Website up and running within minutes of server failure!