1---2name: cloud-architecture3description: Multi-cloud, VPC design, high availability, disaster recovery, and cost optimization4---5
6# Cloud Architecture
7
8Design resilient, cost-effective cloud architectures.
9
10## Design Pillars
11
12| Pillar | Focus | Pattern |
13|--------|-------|---------|
14| Reliability | Fault tolerance, recovery | Multi-AZ, redundancy, auto-healing |
15| Security | Defense in depth | IAM, encryption, network segmentation |
16| Cost | Efficiency, waste reduction | Right-sizing, reserved instances, autoscaling |
17| Performance | Speed, scalability | CDN, caching, horizontal scaling |
18| Operational | Manageability, automation | IaC, CI/CD, runbooks |
19
20## VPC Design
21
22### Multi-Tier Architecture
23```
24Internet → WAF → ALB → App Tier (private) → DB Tier (private)
25 ↕
26 Auto Scaling
27```
28
29### Best Practices
30- Use multiple AZs (minimum 3)
31- Private subnets for apps and databases
32- Public subnets only for load balancers and bastions
33- NACLs for subnet-level rules, Security Groups for instance-level
34- VPC peering or Transit Gateway for multi-VPC
35
36## High Availability
37- **Compute**: Multi-AZ Auto Scaling groups, spot + on-demand mix
38- **Database**: Multi-AZ RDS, Aurora read replicas
39- **Storage**: S3 (11 9's durability), EBS snapshots
40- **DNS**: Route53 with health-check based failover
41- **CDN**: CloudFront/CloudFlare for global distribution
42
43## Disaster Recovery
44
45| Strategy | RTO | RPO | Cost |
46|----------|-----|-----|------|
47| Backup & Restore | Hours | 24h | $ |
48| Pilot Light | Minutes | 1h | $$ |
49| Warm Standby | Seconds | Minutes | $$$ |
50| Active-Active | Seconds | Seconds | $$$$ |
51
52### DR Plan
53- Document runbooks for each scenario
54- Test failover quarterly
55- Automate recovery with IaC
56- Store backups in separate region
57- Encrypt everything
58
59## Cost Optimization
60- Right-size instances (use Compute Optimizer)
61- Reserved Instances / Savings Plans for steady state
62- Spot instances for fault-tolerant workloads
63- S3 lifecycle policies (transition to Glacier)
64- Delete unused resources (EBS, EIP, ELB)
65- Monitor with Cost Explorer + budgets + alerts
gabrielmoreira