Site Loader

Within the discussion of cloud computing there are several concepts that get tossed around and mixed up.  Part of the reason for this is that there are several cloud architecture types.  While there are tons of types and sub-types discussed I’ll focus on four major deployment models here: Public Cloud, Private Cloud, Community Cloud and Hybrid Cloud.  Each cloud type can be used to deliver any combination of XaaS.  The key requirements to be defined as a cloud architecture are:

  • The ability to measure the service being provided
  • Broad Network Access
  • Self-Service
  • Resource Pooling
  • Elasticity

I’ve discussed the business drivers for a transition to cloud in a previous post ( and the technical drivers here (

Public Clouds:

According to NIST with Public Clouds ‘The cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services’ (  This is the service model for cloud computing, A company owns the resources that provide a service and sell that service to other users/companies.  This is a similar model to the utilities, companies pay for the amount of: infrastructure, processing, etc. that is use.  Examples of Public Cloud providers are:

  • Amazon Web Services
  • Rackspace
  • Newservers
  • Verizon
  • Savvis

These and more can be found on Search Cloud Computing’s Top 10 list (


 Private Clouds:

NIST defines the Private Cloud as: ‘The cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on premise or off premise.’

Private clouds are data center architectures owned by a single company that provide flexibility, scalability, provisioning, automation and monitoring.  The goal of a private cloud is not to sell XaaS to external customers but instead to gain the benefits of a cloud architecture without giving up the control of maintaining your own data center.  Typical private cloud architectures will be built on a foundation of end-to-end virtualization, with automation, monitoring, and provisioning tools layered on top.  While not in the definition of Private Clouds bear in mind that security should be a primary concern at every level of design.

There are several complete Private Cloud offerings from various industry leading vendors.  These solutions typically have the advantages joint testing, and joint support among others.  That being said Private Clouds can be built on any architecture you choose.


Community Clouds:

Community Clouds are when an ‘infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on premise or off premise’ according to NIST.

A community cloud is a cloud service shared between multiple organizations with a common tie.  These types of clouds are traditionally thought of as farther out in the timeline of adoption.


Hybrid Clouds:

So while you can probably guess what a hybrid cloud is I’ll give you the official NIST definition first: ‘The cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds).

Using a Hybrid approach companies can maintain control of an internally managed private cloud while relying on the public cloud as needed.  For instance during peak periods individual applications, or portions of applications can be migrated to the Public Cloud.  This will also be beneficial during predictable outages: hurricane warnings, scheduled maintenance windows, rolling brown/blackouts.



When defining a cloud strategy for your organization or customer’s organization it is important to understand the different models and the advantages each can have for a given workload.  No cloud model is mutually exclusive and many organizations will be able to benefit from more than one model at the same time.

Defining a long term vision now and developing a staged migration path to it with set timelines will help ease the transition into cloud based architectures and allow a faster ROI.

When Cloud Goes Bad:


Post Author: Joe Onisick (@JoeOnisick)

3 Replies to “Cloud Types”

Leave a Reply

Your email address will not be published. Required fields are marked *

Shopping cart

Shipping and discount codes are added at checkout.