3 Tier Architecture In AWS | Demo of 3-tier web app in AWS with VPC, ALB...

What is  3-tier architecture in AWS:

The display layer, the business logic layer, and the data storage layer are the three logical tiers that are divided up into the application in a three-tier design. A client-server application with a front end, a back end, and a database, like a web application, uses this design. Each of these tiers or layers can be handled independently of the others and performs a particular function. This is a departure from the monolithic approach of application development, in which the frontend, the backend, and the database are all housed in the same location.

AWS is a cloud computing platform that offers consumers a variety of cloud computing services. Click on this link to see a list of all AWS services and goods. In this post, we'll use the Elastic Compute Cloud (EC2), Auto Scaling Group, Virtual Private Cloud (VPC), Elastic Load Balancer (ELB), Security Groups, and Internet Gateway AWS services to plan and create a three-tier cloud infrastructure. Our infrastructure will be created to be fault resistant and highly available.

                         

Advantages of 3-tier Architecture:

A. HA i.e. Highly Available:

Our application is located in a single place when using a conventional data center. Our application won't be accessible if there is an earthquake, flooding, or even a power outage in the area where it is housed. By hosting our application in many places known as availability zones on AWS, we can design our infrastructure to be highly available.

B. Modularity:

Having a three-tier design is essential for modularizing our application so that each component can be controlled separately from the others. Teams can concentrate on various application levels and make changes as rapidly as feasible because to modularity. Additionally, modularization speeds up recovery from an unplanned catastrophe by concentrating just on the problematic component.

C. Scalability:

To accommodate the traffic and request demand going to it, each tier of the architecture may scale horizontally. This is simply accomplished by increasing the number of EC2 instances in each tier and load distributing among them. We can easily scale the backend tier by adding more EC2 instances to it so that the burden may be dispersed, for example, assuming we have two EC2 instances running our backend application and each of the EC2 instances is working at 80% CPU utilization. When the load is lower, we can also automatically decrease the number of EC2 instances.

D. Secure:

We want to create a highly secure infrastructure that is shielded from snooping hackers. We want to keep any online exposure of our interactions with the application to a minimum. Simply put, this means that the application will use a private IP to communicate among itself. The infrastructure's presentation (frontend) tier will be located in a private VPC subnet (a subnet without any instances with public IP addresses assigned to it). The frontend is only accessible to users via the application load balancer. Because we don't want to expose the backend and database tier to the public internet, they will also be in the private subnet. We'll set up a NAT gateway and the Bastion host for remote SSH. 

E. Fault Tolerant:

Our infrastructure must be able to react without difficulty to any unforeseen change in traffic or problem. This is typically accomplished by including a backup mechanism that will take into account any eventual increase in traffic. Therefore, we have an extra instance making it three instances working at roughly 35% each rather than two EC2 instances working at 50% each, ensuring that when one instance goes bad, the other instance will be running at 100% capacity until a new instance is brought up by our Auto Scaling Group. This is typically weighed against the expense of installing a redundant system.

Follow the link to create machine:

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-lamp-amazon-linux-2023.html

Commands for php application server for each server 

sudo dnf update -y

sudo dnf install -y httpd wget php-fpm php-mysqli php-json php php-devel

sudo systemctl start httpd

sudo systemctl enable httpd

sudo systemctl is-enabled httpd

sudo usermod -a -G apache ec2-user

exit

groups

curl http://localhost

sudo chown -R ec2-user:apache /var/www

sudo chmod 2775 /var/www && find /var/www -type d -exec sudo chmod 2775 {} \;

find /var/www -type f -exec sudo chmod 0664 {} \;

sudo dnf install php-mbstring php-xml -y

sudo systemctl restart httpd

sudo systemctl restart php-fpm

cd /var/www/html

wget https://www.phpmyadmin.net/downloads/phpMyAdmin-latest-all-languages.tar.gz

mkdir phpMyAdmin && tar -xvzf phpMyAdmin-latest-all-languages.tar.gz -C phpMyAdmin --strip-components 1

rm phpMyAdmin-latest-all-languages.tar.gz

sudo systemctl is-enabled httpd

echo "PHP Server 1" >index.html  do for php server1 

echo "PHP Server 2" >index.html  do for php server2

sudo systemctl is-enabled httpd

my-alb-902956905.ap-south-1.elb.amazonaws.com

after cd phpMyAdmin

mv config.sample.inc.php  config.inc.php

vi config.inc.php

replace host with ALB DNS Name Entry

user data for ec2 instances 

#!/bin/bash

yum update -y

yum update httpd -y

systemctl restart httpd

Application Server user data

#!/bin/bash

yum update -y

wget http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-apache-maven.repo -O /etc/yum.repos.d/epel-apache-maven.repo

sed -i s/\$releasever/6/g /etc/yum.repos.d/epel-apache-maven.repo

yum install -y apache-maven

yum install java-1.8.0-openjdk-devel.x86_64 -y

db-server 

#!/bin/bash

yum update -y

yum install mysql

ssh-add -K dev-account.pem

ssh -A ec2-user@<dns-name>

ssh ec2-user@<ip-address-application-server>

Login to web-server OR jump server

from there login to php-app-server

install 

sudo yum update -y

sudo amazon-linux-extras install -y lamp-mariadb10.2-php7.2 php7.2

sudo yum install -y httpd24 php72 mysql57-server php72-mysqlnd

sudo yum install -y httpd

sudo systemctl start httpd

sudo systemctl enable httpd

sudo systemctl is-enabled httpd

curl http://localhost

sudo usermod -a -G apache ec2-user

sudo chown -R ec2-user:apache /var/www

sudo chmod 2775 /var/www && find /var/www -type d -exec sudo chmod 2775 {} \;

find /var/www -type f -exec sudo chmod 0664 {} \;

sudo yum install php-mbstring php-xml -y

sudo systemctl restart httpd

sudo systemctl restart php-fpm

cd /var/www/html

echo "PHP Server 1" >index.html  do for php server1 

echo "PHP Server 2" >index.html  do for php server2

wget https://www.phpmyadmin.net/downloads/phpMyAdmin-latest-all-languages.tar.gz

mkdir phpMyAdmin && tar -xvzf phpMyAdmin-latest-all-languages.tar.gz -C phpMyAdmin --strip-components 1

rm phpMyAdmin-latest-all-languages.tar.gz

Networking:

vpc

webserver, appserver, db server

subnets - public and private subnets

route tables

associations with subnects

Internet gateway for public subet

NAT gateway for private subnets  can communicate to web internet to download patches

create route to Internet Gateway and NAT gateway

Create JUMP server -

craeating EC2 instances for web server hosting in public subnets, allow internet access, 

new securty group as web-sg, allow ssh conectivity

Create PHP server -

creating EC2 instances for app server in private subnets , allow access only from web-sg

Installing PHP, Apache

Installing phpMyAdmin App

create & configue ALB  

create RDS instances and associate db subnet ,as RDS instances

Configuer PHPmyAdmin with RDS 

Try login to appserver via webserver

modify config file to connect to RDS endpoint

Confire Session Stickyness

access the web app server using the URL from web

it shall connect to DB server

Thanks

DataPundit Group

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