It governs the trust boundaries, identities, traffic, data movement, operations, and responsibilities created when those cloud environments work together.
Industry usage sometimes calls any on-premises and public-cloud combination hybrid cloud. Under NIST’s narrower definition, each component is cloud infrastructure; the term hybrid IT is clearer when conventional systems are included. Connection does not create common policy, identity, telemetry, or availability behavior.
Key points
Boundary designInventory every inter-environment link and broker, authenticate endpoints and workloads, restrict permitted flows, protect routing and name resolution, and avoid treating either side as implicitly trusted.
Control translationDefine equivalent intent for identities, data, network policy, configuration, logging, and change control, then use each environment’s native mechanisms and responsibility model.
Data and resilienceTrack data storage, processing, backups, and logs; govern keys and transfers; and test outages, dependency failures, recovery, and disconnection.
Important limitationA unified console or private connection does not make separate clouds one security boundary. Policy translation can lose meaning, shared identity or management can concentrate risk, and an unsafe bridge may expose both environments. Data location, provider access, and contractual responsibilities still differ.