Multi-Cloud Guide
Multi-Cloud vs Hybrid Cloud
| Strategy | Definition | Benefit | Challenge |
|---|---|---|---|
| Multi-Cloud | Using 2+ public clouds (AWS + GCP, etc.) | Avoid vendor lock-in, leverage best services | Operational complexity, skill overhead |
| Hybrid Cloud | On-premises + one or more public clouds | Data sovereignty, legacy integration | Network latency, consistent tooling |
| Polycloud | Different services from different clouds per workload | Best-of-breed services | Data gravity, egress costs |
| Single Cloud | All-in on one provider | Simplicity, deep integration, discounts | Vendor lock-in, risk concentration |
Cloud-Neutral Abstraction Layers
| Layer | Tool / Standard | What It Abstracts |
|---|---|---|
| Infrastructure | Terraform / OpenTofu / Pulumi | VM, network, storage provisioning |
| Containers | Kubernetes (any cloud) | Compute scheduling, service discovery |
| Service Mesh | Istio / Linkerd | Traffic management, mTLS, observability |
| Storage | Rook-Ceph, MinIO (S3-compatible) | Object/block storage portability |
| CI/CD | GitHub Actions, ArgoCD, Tekton | Cloud-agnostic pipelines |
| Observability | OpenTelemetry, Prometheus, Grafana | Metrics, traces, logs across clouds |
| Secrets | HashiCorp Vault | Centralized secret management |
Workload Placement Patterns
# Pattern 1: Best-of-breed services
# - ML/AI workloads → GCP (Vertex AI, TPUs)
# - Existing .NET / Azure AD → Azure
# - Core infrastructure → AWS (most mature ecosystem)
# Pattern 2: Active-active disaster recovery
# - Same workload runs on AWS + GCP simultaneously
# - Global load balancer (Cloudflare) distributes traffic
# - Data replicated across clouds (expensive egress!)
# Pattern 3: Arbitrage / cost optimization
# - Use spot instances across clouds; pick cheapest
# - Tools: Spot.io (Flexera), ProsperOps
# Pattern 4: Regulatory / data residency
# - EU customer data → Azure Europe (GDPR)
# - US government → AWS GovCloud
# - China market → separate cloud (Alibaba Cloud / Tencent)
# Kubernetes federation (distribute across clouds)
# kubectl ctx cluster-aws → deploy to AWS EKS
# kubectl ctx cluster-gcp → deploy to GCP GKE
# Kubefed / Flux Multi-cluster for automated federation