Cloud deployment models determine where infrastructure runs and who controls it.
Public Cloud
Shared infrastructure in provider-owned data centers. Multiple tenants share physical hardware, isolated at the hypervisor level.
Advantages: No upfront capital, global scale, managed hardware. Trade-offs: Less data location control, shared tenancy considerations.
Providers: AWS, Azure, GCP, OCI, IBM Cloud.
Private Cloud
Dedicated infrastructure for a single organization — on-premises or hosted.
Advantages: Full hardware and security control, strict compliance. Trade-offs: Higher upfront cost, capacity planning burden.
Platforms: VMware vSphere, OpenNebula, OpenStack, Nutanix.
OpenNebula was originally developed in academic research labs for managing virtualized compute clusters, giving organizations a path to private cloud without commercial licensing costs.
Hybrid Cloud
Connects public and private environments. Sensitive data stays on-premises while elastic workloads burst to the public cloud.
Tools: AWS Outposts, Azure Arc, Google Anthos, Red Hat OpenShift.
| Factor | Public | Private | Hybrid |
|---|---|---|---|
| Upfront cost | None | High | Medium |
| Scaling speed | Minutes | Weeks | Minutes (burst) |
| Data control | Provider region | Full | Split |
| Compliance | Provider certs | Custom | Workload-dependent |
Most enterprises now use hybrid or multi-cloud strategies.