Multi Cloud Architecture

1---2name: multi-cloud-architecture3description: Design multi-cloud architectures using a decision framework to select and integrate services across AWS, Azure, GCP, and OCI. Use when building multi-cloud systems, avoiding vendor lock-in, or leveraging best-of-breed services from multiple providers.4---5 6# Multi-Cloud Architecture7 8Decision framework and patterns for architecting applications across AWS, Azure, GCP, and OCI.9 10## Purpose11 12Design cloud-agnostic architectures and make informed decisions about service selection across cloud providers.13 14## When to Use15 16- Design multi-cloud strategies17- Migrate between cloud providers18- Select cloud services for specific workloads19- Implement cloud-agnostic architectures20- Optimize costs across providers21 22## Cloud Service Comparison23 24### Compute Services25 26| AWS     | Azure               | GCP             | OCI                 | Use Case           |27| ------- | ------------------- | --------------- | ------------------- | ------------------ |28| EC2     | Virtual Machines    | Compute Engine  | Compute             | IaaS VMs           |29| ECS     | Container Instances | Cloud Run       | Container Instances | Containers         |30| EKS     | AKS                 | GKE             | OKE                 | Kubernetes         |31| Lambda  | Functions           | Cloud Functions | Functions           | Serverless         |32| Fargate | Container Apps      | Cloud Run       | Container Instances | Managed containers |33 34### Storage Services35 36| AWS     | Azure           | GCP             | OCI            | Use Case       |37| ------- | --------------- | --------------- | -------------- | -------------- |38| S3      | Blob Storage    | Cloud Storage   | Object Storage | Object storage |39| EBS     | Managed Disks   | Persistent Disk | Block Volumes  | Block storage  |40| EFS     | Azure Files     | Filestore       | File Storage   | File storage   |41| Glacier | Archive Storage | Archive Storage | Archive Storage | Cold storage   |42 43### Database Services44 45| AWS         | Azure            | GCP           | OCI                 | Use Case        |46| ----------- | ---------------- | ------------- | ------------------- | --------------- |47| RDS         | SQL Database     | Cloud SQL     | MySQL HeatWave      | Managed SQL     |48| DynamoDB    | Cosmos DB        | Firestore     | NoSQL Database      | NoSQL           |49| Aurora      | PostgreSQL/MySQL | Cloud Spanner | Autonomous Database | Distributed SQL |50| ElastiCache | Cache for Redis  | Memorystore   | OCI Cache           | Caching         |51 52**Reference:** See `references/service-comparison.md` for complete comparison53 54## Multi-Cloud Patterns55 56### Pattern 1: Single Provider with DR57 58- Primary workload in one cloud59- Disaster recovery in another60- Database replication across clouds61- Automated failover62 63### Pattern 2: Best-of-Breed64 65- Use best service from each provider66- AI/ML on GCP67- Enterprise apps on Azure68- Regulated data platforms on OCI69- General compute on AWS70 71### Pattern 3: Geographic Distribution72 73- Serve users from nearest cloud region74- Data sovereignty compliance75- Global load balancing76- Regional failover77 78### Pattern 4: Cloud-Agnostic Abstraction79 80- Kubernetes for compute81- PostgreSQL for database82- S3-compatible storage (MinIO)83- Open source tools84 85## Cloud-Agnostic Architecture86 87### Use Cloud-Native Alternatives88 89- **Compute:** Kubernetes (EKS/AKS/GKE/OKE)90- **Database:** PostgreSQL/MySQL (RDS/SQL Database/Cloud SQL/MySQL HeatWave)91- **Message Queue:** Apache Kafka or managed streaming (MSK/Event Hubs/Confluent/OCI Streaming)92- **Cache:** Redis (ElastiCache/Azure Cache/Memorystore/OCI Cache)93- **Object Storage:** S3-compatible API94- **Monitoring:** Prometheus/Grafana95- **Service Mesh:** Istio/Linkerd96 97### Abstraction Layers98 99```100Application Layer101    ↓102Infrastructure Abstraction (Terraform)103    ↓104Cloud Provider APIs105    ↓106AWS / Azure / GCP / OCI107```108 109## Cost Comparison110 111### Compute Pricing Factors112 113- **AWS:** On-demand, Reserved, Spot, Savings Plans114- **Azure:** Pay-as-you-go, Reserved, Spot115- **GCP:** On-demand, Committed use, Preemptible116- **OCI:** Pay-as-you-go, annual commitments, burstable/flexible shapes, preemptible instances117 118### Cost Optimization Strategies119 1201. Use reserved/committed capacity (30-70% savings)1212. Leverage spot/preemptible instances1223. Right-size resources1234. Use serverless for variable workloads1245. Optimize data transfer costs1256. Implement lifecycle policies1267. Use cost allocation tags1278. Monitor with cloud cost tools128 129**Reference:** See `references/multi-cloud-patterns.md`130 131## Migration Strategy132 133### Phase 1: Assessment134 135- Inventory current infrastructure136- Identify dependencies137- Assess cloud compatibility138- Estimate costs139 140### Phase 2: Pilot141 142- Select pilot workload143- Implement in target cloud144- Test thoroughly145- Document learnings146 147### Phase 3: Migration148 149- Migrate workloads incrementally150- Maintain dual-run period151- Monitor performance152- Validate functionality153 154### Phase 4: Optimization155 156- Right-size resources157- Implement cloud-native services158- Optimize costs159- Enhance security160 161## Best Practices162 1631. **Use infrastructure as code** (Terraform/OpenTofu)1642. **Implement CI/CD pipelines** for deployments1653. **Design for failure** across clouds1664. **Use managed services** when possible1675. **Implement comprehensive monitoring**1686. **Automate cost optimization**1697. **Follow security best practices**1708. **Document cloud-specific configurations**1719. **Test disaster recovery** procedures17210. **Train teams** on multiple clouds173 174 175## Related Skills176 177- `terraform-module-library` - For IaC implementation178- `cost-optimization` - For cost management179- `hybrid-cloud-networking` - For connectivity