htlin222/cloud

Cloud Architecture

Design and manage cloud infrastructure.

When to Use

• Cloud architecture decisions
• Cost optimization
• Multi-region deployments
• Cloud migrations
• Infrastructure automation

AWS Patterns

Compute

# ECS Service
Resources:
  Service:
    Type: AWS::ECS::Service
    Properties:
      Cluster: !Ref Cluster
      DesiredCount: 2
      LaunchType: FARGATE
      NetworkConfiguration:
        AwsvpcConfiguration:
          Subnets: !Ref PrivateSubnets
          SecurityGroups: [!Ref SecurityGroup]

Serverless

# Lambda with API Gateway
functions:
  api:
    handler: src/handler.main
    events:
      - http:
          path: /users
          method: get
    environment:
      TABLE_NAME: !Ref UsersTable

Database

# RDS with read replica
resource "aws_db_instance" "primary" {
  identifier     = "app-primary"
  engine         = "postgres"
  engine_version = "15"
  instance_class = "db.r6g.large"
  multi_az       = true
}

resource "aws_db_instance" "replica" {
  identifier          = "app-replica"
  replicate_source_db = aws_db_instance.primary.identifier
  instance_class      = "db.r6g.large"
}

Cost Optimization

Compute

• Use Spot/Preemptible for fault-tolerant workloads (70% savings)
• Right-size instances based on actual usage
• Reserved instances for steady-state workloads (40% savings)
• Auto-scaling based on demand

Storage

• S3 lifecycle policies for infrequent access
• EBS volume type selection (gp3 vs io2)
• Delete unused snapshots and volumes

Network

• Use VPC endpoints to avoid NAT costs
• CloudFront for static content
• Compress and cache responses

Multi-Region

┌─────────────────┐     ┌─────────────────┐
│   us-east-1     │     │   eu-west-1     │
│ ┌─────────────┐ │     │ ┌─────────────┐ │
│ │ Application │ │     │ │ Application │ │
│ └──────┬──────┘ │     │ └──────┬──────┘ │
│        │        │     │        │        │
│ ┌──────┴──────┐ │     │ ┌──────┴──────┐ │
│ │  Database   │◄├─────┼►│   Replica   │ │
│ └─────────────┘ │     │ └─────────────┘ │
└─────────────────┘     └─────────────────┘
         │                       │
         └───────────┬───────────┘
                     │
              ┌──────┴──────┐
              │ Route 53    │
              │ (failover)  │
              └─────────────┘

Security Baseline

• [ ] VPC with private subnets
• [ ] Security groups (least privilege)
• [ ] IAM roles (not keys)
• [ ] Encryption at rest and transit
• [ ] CloudTrail logging
• [ ] GuardDuty enabled

Examples

Input: "Design HA architecture" Action: Multi-AZ setup, load balancing, database replication, failover

Input: "Reduce cloud costs" Action: Analyze usage, identify waste, recommend reserved/spot, optimize storage