Understanding Hybrid Cloud: Definitions, Types, Architecture, and Design Principles

Hybrid cloud lacks a precise definition, but according to NIST it can be described as an IT architecture that interconnects multiple clouds.

Four typical hybrid‑cloud forms are identified: public‑public cloud mixing, private‑private cloud mixing, public‑private cloud mixing, and public‑traditional IT mixing.

Compared with multi‑cloud, hybrid cloud requires dedicated links (e.g., leased lines or VPN) for inter‑cloud communication, while multi‑cloud relies on cloud‑management platforms; hybrid cloud focuses on inter‑cloud connectivity for application interaction, whereas multi‑cloud emphasizes resource management via open APIs.

The article then analyses each hybrid‑cloud form, noting that public‑public mixing often uses tools like HashiCorp Terraform to abstract infrastructure differences, private‑private mixing usually occurs within a single organization, public‑private mixing is the current hotspot, and public‑traditional IT mixing extends the definition of hybrid cloud by including on‑premise data‑center resources.

Hybrid‑cloud architecture combines private, dedicated, public clouds and on‑premise IDC resources, offering advantages over single‑cloud solutions but demanding higher design and deployment effort. Key architectural characteristics include:

Elasticity: the ability to scale horizontally across clouds during peak loads and release resources during low demand.

Scalability: unified APIs enable seamless resource orchestration across heterogeneous platforms, including Kubernetes federation and virtual nodes.

Security: increased boundary complexity requires unified security management, integration of cloud‑native protections (DDoS, WAF), and data encryption for compliance.

Design goals are summarized as the “five‑connectivity” model—data center connectivity, network connectivity, data connectivity, application connectivity, and management connectivity—illustrated in Figure 1.

These goals align with the broader “new‑infrastructure” initiative, where cloud computing serves as the foundational layer supporting 5G, IoT, satellite internet, and AI, driving digital transformation across industries.

Finally, the article cites Gartner and IDC forecasts that hybrid cloud will dominate the cloud market, becoming the primary architecture for new‑infrastructure deployments.