Why multi-cloud:
- Avoid vendor lock-in
- Regulatory requirements
- Best-of-breed services
- Disaster recovery
Challenges:
- Increased complexity
- Different APIs and concepts
- Networking between clouds
- Skills requirements
Patterns:
- Active-active: Both clouds serve traffic
- DR: Secondary cloud for failover only
- Service split: Different workloads on different clouds
Interview question: "Should we use multi-cloud?"
Usually no, unless you have specific requirements. The complexity cost is high. Most companies benefit more from deep expertise in one cloud than shallow knowledge of many.