Client-server Achitecture With Mysql

Overview:

In a client-server architecture, the client requests data or services, and the server responds with the requested information. For a MySQL-based architecture, the client would communicate with a MySQL server, where the database operations such as queries, inserts, updates, and deletions occur.

Architecture Components:

• Client: Could be a web app (browser), desktop app, mobile app, or backend API. Sends requests (e.g., HTTP or direct DB queries) to the server for data.

• Server: Contains the business logic (usually a backend server, such as Node.js, FastAPI, or a PHP server). Interacts with the MySQL database to retrieve or modify data. Sends the response back to the client.

• MySQL Database: Stores the data. Responds to queries from the server to fetch or update data.

To demonstrate the client server architecture, we will follow the following steps:

Steps

Step 1 Create and configure two Linux-based virtual servers

• We will launch two ubuntu instances on AWS named mysql-server and mysql-client

Note the public-IP of the mysql-client server

In this case, mine is 98.80.124.104

• Open security groups ports on 3306, the default mySQL port on mysql-server from the specific IP of the mysql-client

The only ports open on our mysql-server are 3306 for database access 22 for server configurations.

• We will open SSH, HTTP, and HTTPs access on the mysql-client server so that we can access it from our local system and from anywhere. Also, to simulate real time client.

A and B are specific IP ranges for EC2-instance-connect and my local IP range respectively.

SSH into both servers. I will be using the EC2 instance connect. You can also access the server from your local system via SSH.

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Step 2 Install MySQL-server and Configure mysql-server to allow connections form remote hosts.

• Install MYSQL server software on mysql-server

# Update apt repo
sudo apt update -y

# install mysql-server
sudo apt install mysql-server -y

# Verify and enable mysql
sudo systemctl status mysql

sudo systemctl enable mysql

sudo systemctl restart mysql

# login to the mysql console
sudo mysql

Set the root user password:

ALTER USER 'root'@'localhost' IDENTIFIED BY 'Passw0rd123#';

We are using the above password for demonstration purpose. In production, a more secure password should be set.

Exit the mysql shell:

exit

• Secure mysql installation, following the prompts:

sudo mysql_secure_installation

• Configure remote access. Edit the mysqld.cnf file, replacing the bind-address port on localhost 127.0.0.1 with 0.0.0.0 .

Look for the line that starts with bind-address. This defines which IP addresses MySQL will listen to. By default, it's set to 127.0.0.1 (localhost), which means only local connections are allowed.

Change this line to 0.0.0.0 to allow MySQL to listen on all network interfaces, or you can specify a specific IP address for better security.

sudo vi /etc/mysql/mysql.conf.d/mysqld.cnf

Save and exit the file.

Step 3 Install MySQL-client on mysql-client server.

The MySQL client is a command-line tool that allows you to connect to and interact with MySQL databases, whereas the MySQL server is the actual database engine that stores and manages data.

• Navigate to the mysql-client server.

• Install mysql-client:

# Update apt repository
sudo apt update -y

# Install mysql-client
sudo apt install mysql-client -y

Step 4 Connect to mysql-server via mysql-client Linux server.

From the mysql-client Linux server, connect remotely to mysql-server database engine without SSH. To do this we will need to use the mysql utility.

First create a remote user named remote_user on mysql-server:

• Login to MySQL database on the mysql-server with the root user.

sudo mysql -u root -p

• Create a new user named remote-user and grant all privileges to the user:

CREATE USER 'remote_user'@'%' IDENTIFIED BY 'Passw0rd321#';

GRANT ALL PRIVILEGES ON *.* TO 'remote_user'@'%' WITH GRANT OPTION;

FLUSH PRIVILEGES;

Exit the mysql console.

exit

'%' allows you to connect from any IP. It can be replaced with a specific IP for improved security.

Restart mysql.

sudo systemctl restart mysql

Remember we have opened our security group inbound rule on 3306. It should be done at this point, if not done already.

We must also open the ubuntu UFW (uncomplicated Firewall) on port 3306: First verify that ufw is set to inactive. If it is, skip this step.

sudo ufw allow 3306/tcp

Verify the firewall rule:

sudo ufw status

Finally, connect remotely using the mysql client from the mysql-client server:

mysql -h [mysql-server-ip] -u [username] -p

for instance, in my case, 3.82.5.9 is the mysql-server public -IP

mysql -h 3.82.5.9 -u remote_user -p 

# You will be prompted to enter the password for remote user which in our case is `Passw0rd321#`

• Run some database commands from mysql-client server to verify remote access:

/*show databases*/

SHOW databases;

• Create database and table

/* Create database, create table */

CREATE DATABASE demo_db;

USE demo_db;

CREATE TABLE users (
  id INT AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(100),
  email VARCHAR(100),
  age INT
);

INSERT INTO users (name, email, age) VALUES
('Alice', 'alice@example.com', 25),
('Bob', 'bob@example.com', 30),
('Charlie', 'charlie@example.com', 35);

Show tables:

SHOW TABLES;

Note that we performed this actions from the mysql-client server, thereby demonstrating the client-server architecture

Conclusion

We have successfully demonstrated a client-server architecture.