Cloud Computing Term Matrix



  • There are several axis on which clouds can exist. Understanding these is key to understanding cloud terms.

    First: Cloud Computing is an architecture for computing platforms, nothing more. It has no other implications.


    Axis One: Hosted vs. On Premises: Any cloud infrastructure can be hosted or on premises. A hosted cloud is just like any other hosted product, it is run off premises by someone else. Large companies commonly run their own clouds on premises for fast, local LAN connectivity to it. The normal hosted vs. on premises decisions apply. Hosted in your own colocation location is, obviously, an option.

    Common cloud computing hosts include Amazon, Azure, Vultr, Digital Ocean, Softlayer / IBM, Rackspace, Linode, Railyard, Joyent, OpenShift and Heroku.

    Common cloud computing software includes vCloud from VMware, OpenStack, Cloud Stack and more.


    Axis Two: Private vs. Public: Any cloud can be single tenant or multi-tenant. A dedicated cloud for a single customer is called a private cloud. One that is shared among multiple customers is called a public cloud. Typically private cloud brings vastly higher costs but with many more options and customization. Public cloud is often more secure due to anonymity creation.

    Obviously it is weird and unlikely for on-premises clouds to be public, but there is nothing that stops this since any hosted cloud is on premises to someone (Amazon's EC2 is local to Amazon, for example.)

    Some hosted cloud providers provide private cloud options such as Amazon, Azure and Rackspace. Some, like Vultr and Digital Ocean, do not. All cloud software can be private or public depending on use.


    Axis Three: IaaS, PaaS, SaaS: Cloud computing is offered at one (or more) of three defined service levels providing different interfaces. IaaS provides a place to deploy VMs or containers. PaaS is a platform for deploying software. SaaS is software provided directly as a consumable application.

    Common IaaS providers are: Amazon, Azure, Vultr, Digital Ocean, Linode, etc.

    Common PaaS provders are: Heroku, Joyent, Railyard, Amazon, Azure

    Common SaaS providers are: G Suite, Office 365, SalesForce

    Common IaaS software: OpenStack, vCloud

    Common PaaS software: OpenShift

    Common SaaS software: N/A

    Note 1: The nature of SaaS is that end users never know or care if there is a cloud under the application unless the vendor discloses it. Caring about SaaS cloud nature is irrelevant to end users.

    Note 2: IaaS, PaaS and SaaS all exist in both cloud and non-cloud options. The use of IaaS, for example, does not mean that it is also a cloud.



  • The variety of cloud options can make things very confusing. Here are some varying circumstances:

    1. Amazon EC2 is available in both public and private models, both hosted and on premises. It also provides IaaS, PaaS and SaaS interfaces!

    2. OpenStack software can be deployed anywhere you want and is available as a hosted product from vendors like Rackspace. So OpenStack is available for both public and private use, both hosted and on-premises. OpenStack itself only does IaaS, but it can be used as a basis for PaaS and/or SaaS on top of it.



  • Thanks.