Not all clouds are built the same way, and the model you choose shapes everything downstream: how you secure workloads, manage costs, meet compliance requirements, and scale over time. Here's what each model actually means in practice.
Public Clouds
Public clouds are a type of cloud computing that provides storage, compute and networking services, software, and facilities on demand via the internet. Public clouds are multi-tenant environments, meaning multiple customers will share the underlying resources that are owned and operated by the cloud service provider (CSP). Popular public cloud vendors include Amazon Web Services (AWS), Microsoft’s Azure, Google Cloud Platform (GCP), and Oracle Cloud Infrastructure (OCI).
Private Clouds
A private cloud is typified by resources dedicated to a single customer; no other customers will share the underlying resources (hardware and perhaps software). Therefore, private clouds are not multi-tenant environments. Instead, an organization might own and operate a private cloud as the sole customer; or the organization might contract with a cloud provider for exclusive use of specific resources inside what otherwise would be a public cloud; or a cloud provider installs hardware/software inside the customer’s data center – the customer controls the data plane and consumes the resources while the cloud provider owns the hardware/software and takes the ownership of the control plane.
Hybrid Clouds
A hybrid cloud contains elements of the private cloud services, public cloud services, and on-premises infrastructure. For instance, an organization might want to retain some private cloud resources (say, their legacy production environment, which is accessed remotely by their users) but also lease some public cloud space (maybe a Platform-as-a-Service (PaaS) function for software development/testing, away from the production environment to lessen the risk of crashing operational systems).
Multicloud
Multicloud is a strategy that leverages two or more cloud services and mainly refers to multiple cloud services. Typically, each cloud is managed by a CSP. Also, some researchers treat hybrid clouds and multiclouds as the same concept since both cloud deployment models consist of more than a single infrastructure management mechanism.
Community Clouds
A community cloud features infrastructure and processing owned and operated by (or for) an affinity group; disparate pieces might be owned or controlled by individuals or distinct organizations, but they come together in some fashion to perform joint tasks and functions. It can be provisioned by a third party on behalf of the various members of the community, such as government customers that have similar security/service requirements while needing to be isolated from common public clouds. The gaming industry could be another group of customers who are in favor of community clouds, such as Sony’s PlayStation network that involves many different entities coming together to engage in online gaming.
The deployment model you choose isn't just a procurement decision. It's the foundation your security architecture is built on. Understanding the tradeoffs of each is where smart cloud strategy starts.
