☁️ Cloud কেন?
- No hardware, pay-as-you-go
- Auto-scale, global reach
- Managed service (DB, ML, queue)
📊 Model
IaaS: VM/Storage/Network (EC2, S3) PaaS: managed runtime (Beanstalk) SaaS: ready app (Gmail)
🏢 AWS Infrastructure
- Region — geographic area
- AZ — isolated DC (3+/region)
- Edge — CloudFront CDN
🇧🇩 Bangladesh Regions
- ap-south-1 Mumbai — closest ~50ms
- ap-southeast-1 Singapore — 80ms
- us-east-1 — cheapest 250ms
🆓 Free Tier (12 mo)
EC2: 750h t2.micro/month S3: 5GB RDS: 750h Lambda: 1M req (always free) DynamoDB: 25GB (always) CloudFront: 1TB
🔐 IAM
1. Root → IAM → Add user 2. MFA on root + every user 3. Access key — never commit 4. IAM Role for EC2/Lambda aws configure aws s3 ls
👥 IAM Best Practice
- Root: billing only, MFA, never use
- Least privilege policy
- Group-based (Developer/Admin)
- Role for resource-to-resource
- Rotate keys 90 days
- CloudTrail audit on
💰 Billing Alarm
CloudWatch → Alarm → EstimatedCharges > $10 → SNS Email
🆚 AWS vs Azure vs GCP
AWS: market leader, most service Azure: .NET, enterprise GCP: data/ML, Kubernetes origin
🎓 মূল কথা ⭐
AWS = market default। Free tier 12 মাস utilize করুন। Root lock, IAM user-এ work। Billing Alarm Day 1 — bill shock এড়ান।