Just when you thought you had this whole “cloud computing” thing figured out, in enters a new set of cloud terms to wrap your head around, such as “private cloud”, “hybrid cloud” and “virtualization”.
The confusion is reasonable considering these different words do stem from one place: the cloud.
In order to cut through the fog, let’s look at what constitutes a public cloud and how a private cloud differs. Once those are covered we’ll explain virtualization.
Cloud Computing: Public vs. Private Cloud Environments
Cloud computing is a computing environment where computing resources including servers, CPU time, network, user and application access, are pooled dynamically, and automatically shared on an as-needed basis. This dynamic apportionment of computing resources maximizes efficient use of the system and minimizes the amount of investment in equipment and licensing required to support any given system or user community.
When most people think of cloud computing, they think of the large, public cloud computing providers, particularly specialized Software-as-a-Service providers, such as SalesForce or WorkDay. They might also think of the big name public cloud hosting providers such as Amazon, IBM, Sun, Google and Microsoft.
Public cloud computing services provide all of the characteristics that the National Institutes for Standards in Technology (NIST) have described as essential to a true cloud computing environment. The characteristics include:
2. Self-service for users
3. Broad network access
4. Shared resource pool
5. Elastically scalable resources
6. Measured service
Often, companies find that hosting some or all of their computing resources in a public cloud is an effective option. However, public cloud computing is subject to concerns about systems accessibility for users and about data security. Using a public cloud, after all, does require internet accessibility to be up whenever the users need it, and the word “public” in “public cloud” does carry data security concerns.
When a company wants to gain the efficiencies of cloud computing, without exposure to these two dangers, they choose to configure their in-house computing environment as a private cloud. Often what companies are calling “private clouds” are not true cloud computing environments. According to that report by Forrester Research referenced at the beginning most private clouds are not full cloud computing environments because they lack one or more of the NIST’s characteristics of a cloud.
Private Cloud vs. Virtualization
The system configuration that is the most commonly confused with private cloud computing is virtualization. Virtualization is when software is used to create one or more encapsulated computing environments separate from the operating system of hosting computers. A server or set of servers can host multiple virtual machines, and each virtual machine can be running different operating systems or different suites of applications.
In a relatively static computing environment, these virtual machines offer much of the same benefit as a cloud computing environment, but they do not provide the cloud characteristics of on-demand user self service, nor do they tend to be elastically scalable. Generally, configuration or reconfiguration of a virtual machine requires the intervention of a human IT administrator and might involve delays and downtime while reconfiguration is implemented.
Defining Your Cloud Needs
When an organization needs all of the benefits and characteristics of a true cloud computing environment, but does not want to expose their users and data to the dangers of public cloud computing, they need to evaluate in-house cloud computing support systems.
True cloud computing, such as the IBM iSeries Cloud, help companies and departments to outperform their competitors by maximizing dynamic computing availability and resource efficiency while minimizing human intervention and IT staffing costs.