AWS Lesson 04

1. RDS ဆိုတာ

RDS = Relational Database Service = Managed SQL Database

✅ MySQL, PostgreSQL, MariaDB, Oracle, SQL Server, Aurora support
✅ Automatic backups, patching, failover — AWS ကိုယ်တိုင် manage
✅ Multi-AZ = High availability (auto failover)
✅ Free tier: db.t2.micro, 20GB storage (12 လ)

2. RDS MySQL Create

RDS → Create database

Engine: MySQL · Version: 8.0

Template: Free tier

DB instance: db.t2.micro

Master username: admin · Password: strong password

Storage: 20 GB gp2

VPC: Default · Public access: No (EC2 ကနေပဲ ဝင်)

Security group: EC2 security group ထည့်

Create → ~10 min ကြာမယ်

3. EC2 ကနေ RDS Connect

# EC2 SSH ဝင်ပြီး MySQL client install
sudo apt install mysql-client -y

# RDS endpoint ကို RDS → Databases → Instance မှာ ကြည့်
# Format: xxx.rds.amazonaws.com

# Connect
mysql -h <rds-endpoint> -u admin -p

# Example
mysql -h mydb.abc123.ap-southeast-1.rds.amazonaws.com -u admin -p

# SQL ရေး
CREATE DATABASE my_school;
USE my_school;
SHOW TABLES;

Security group မှာ MySQL (3306) ကို EC2 security group ကနေ allow လုပ်ဖို့ မမေ့နဲ့
EC2 → RDS same VPC ထဲ ဖြစ်ရမယ်

4. PHP မှာ RDS Connect

<?php
$host     = 'mydb.abc123.ap-southeast-1.rds.amazonaws.com';
$dbname   = 'my_school';
$username = 'admin';
$password = 'your-strong-password';

try {
    $pdo = new PDO(
        "mysql:host=$host;dbname=$dbname;charset=utf8mb4",
        $username,
        $password
    );
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    echo "RDS Connected!";
} catch (PDOException $e) {
    die("Connection failed: " . $e->getMessage());
}
?>

// .env file မှာ သိမ်းပါ (code ထဲ မထည့်)
DB_HOST=mydb.abc123.rds.amazonaws.com
DB_NAME=my_school
DB_USER=admin
DB_PASS=your-password

5. Backup & Monitoring

Automatic Backups:
- Default: 7 days retention
- RDS → Modify → Backup retention period: 7-35 days
- Point-in-time recovery support

Manual Snapshot:
- RDS → Databases → Actions → Take snapshot
- ပြန်ထားနိုင်တယ် (restore to point in time)

Monitoring:
- RDS → Monitoring tab → CloudWatch metrics
- CPU, Connections, Free Storage Space ကြည့်

Multi-AZ = Standby replica တစ်ခု auto maintain — primary fail ဖြစ်ရင် auto failover
Production မှာ Multi-AZ ဖွင့်ပါ (extra cost ဖြစ်မယ်)

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