Multi-Cloud and Hybrid Cloud Architecture Questions

Designing systems that span multiple cloud providers or bridge cloud and on-premises. Covers cloud-agnostic abstraction, workload placement across providers or environments, cross-cloud networking and identity federation, data gravity, infrastructure-as-code and centralized observability that span providers, and the operational cost of avoiding vendor lock-in versus the risk of accepting it. Also covers keeping a system correct once it spans providers: leader election, distributed transactions, rate limiting, and service discovery across cloud or cluster boundaries. Resilience patterns here are scoped to crossing a provider or on-prem/cloud boundary (for example failover from one provider to another, or from on-prem to cloud). Resilience across regions of a single provider, with no second provider or on-prem leg involved, is a different topic (multi-region architecture) and is out of scope here.