Deploying a 3-tier application

March 31, 2025

This content originally appeared on DEV Community and was authored by NAVEEN KUMAR

Part I:

(1) Download code from github
(2) Create S3 bucket
(3) IAM Role creation
(4) Create VPC
(5) Create Subnets – 6
(6) Create IG – 1
(7) Create NAT GW – 2
(8) Create Route Tables (public sn, private sn – 2, private db – 2)
(9) Create Security Groups (Internet-1, Web tier-1, Internal-1, App tier-1, DB-1)
(10) Create Database
(11) Create App tier (instance)

I. connect app tier instance in session manager

II. follow the commands:
(i) sudo -su ec2-user
(ii) ping 8.8.8.8
(iii) sudo yum install mysql -y
(iv) mysql -h (CHANGE-TO-YOUR-RDS-ENDPOINT) -u (CHANGE-TO-USER-NAME) -p
(v) (TYPE DB PASSWORD)

III. type the SQL commands:
(i) CREATE DATABASE webappdb;
(ii) SHOW DATABASES;
(iii) USE webappdb;
(iv) CREATE TABLE IF NOT EXISTS transactions(id INT NOT NULL
AUTO_INCREMENT, amount DECIMAL(10,2), description
VARCHAR(100), PRIMARY KEY(id));
(v) SHOW TABLES;
(vi) INSERT INTO transactions (amount,description) VALUES
(‘400′,’groceries’);
(vii) SELECT * FROM transactions;

IV. type ‘exit’ to exit from MySQL client

(12) modify the ‘DBconfig.js’ file in the app tier folder and upload the app tier folder to s3
(13) Back to the SSM, follow the commands:

curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.38.0/install.sh | bash
source ~/.bashrc
nvm install 16
nvm use 16
npm install -g pm2
cd ~/
aws s3 cp s3://BUCKET_NAME/app-tier/ app-tier –recursive
cd ~/app-tier
npm install
pm2 start index.js
pm2 list
pm2 logs
pm2 startup
pm2 save
curl http://localhost:4000/health
curl http://localhost:4000/transaction

(14) Create AMI for the App tier instance
(15) Create Target Group
(16) Create Load Balancer for App tier
(17) Launch Templates
(18) Create Auto Scaling Group
(19) update the ngnix file and upload it along with the WebApp to S3
(20) create an instance for WebApp
(21) connect the instance to SSM
(22) Create AMI for the Web tier instance
(23) Create Target Group
(24) Create Load Balancer for Web tier
(25) Launch Templates
(26) Create Auto Scaling Group