Choosing Between Private and Public Cloud Computing

Are there advantages to having a private cloud network operated within a company’s own infrastructure over having a public cloud? Should smaller companies outsource their servers and information to external public cloud networks like Microsoft’s Azure or Amazon’s Web Services? The difference between public and private cloud computing can be summarized by looking at where the infrastructure or data is being hosted — is it within a company’s own firewall or outside of it? However, the question related to what should a company choose to rely on for its own network and infrastructure is much more complex.
Let’s first take a look at the three main service modules as they relate to cloud computing:

SaaS

Software as a service may refer to something like Google Docs or Microsoft Office 365 which allow you to access productivity suites through the cloud. The advantages are numerous. For example, the cost of this sort of software is generally based on the pay-as-you-go model and this eliminates huge upfront expenses. You don’t have to purchase an entire suite from Microsoft, but instead you can pay a monthly fee for the privilege of having your employees use it. It is also flexible in terms of how many employees have access to the software and the types of features that can be enabled or disabled on demand. In a private cloud, SaaS can also exist within the ranks of the employment force. For example, an e-mail client who is only accessible to the users within the same firewall could fit under private cloud.

IaaS

Infrastructure as a service may reference computers, servers, storage units, and the building blocks of a company’s IT section. IaaS may refer to virtual machines as well as physical hardware.

PaaS

Platform as a service refers to the layer of software hosting that the SaaS sits underneath— and relies on it to function. For example, an operating system can be considered a platform. Many PaaS, including Amazon’s Elastic Compute Cloud (EC2), offer a wide range of platforms and operating systems for companies to choose from or alter — thus offering great elasticity and scalability.
According to Amazon’s EC2 description page, “Amazon EC2 presents a true virtual computing environment, allowing you to use web service interfaces to launch instances with a variety of operating systems, load them with your custom application environment, manage your network’s access permissions, and run your image using as many or few systems as you desire.”
Now let’s take a look at public and private cloud computing and compare their advantages or disadvantages as they relate to companies of different sizes and needs.

Public Cloud

For SMBs and startups public cloud computing makes all the sense in the world. These companies often don’t have much capital and have less risk in losing information due to theft or security breaches. For SMBs, cloud computing saves them a lot of money and the need to build extra infrastructure.
Smaller businesses and startups really enjoy the pay-as-you-go flexibility that public cloud offers and the cost savings associated with it. Most service providers, like Amazon with Web Services and EC2, offer a lot of scalability so businesses can scale their operations only to the needs that they have.
For example, if a company’s demand grows and more employees get hired, the public cloud provider will allow the company to have access to more infrastructure as a service and servers hosting the data that will be need for the additional employees.
David Linthicum, CTO and founder of cloud computing consolidation firm, Blue Mountain labs, emphasized this recently in an interview I conducted with him for another story. He said that a company’s workforce should never see a server and should only bring on-site computing devices like laptops to their workplace. The actual infrastructure should be in a public cloud and any computing device — be it a laptop, tablet, or tower PC — should be able to access it.
However, questions arise when you talk about bigger companies or ones with a lot of sensitive data to keep track of. Should they rely on a public cloud option or host their own private cloud?

Private Cloud

Private cloud makes a lot of sense to these bigger companies because it is based on a model where they run their own servers and infrastructure. The idea is to control your own infrastructure and only allow workers within the same firewall to access all the content from the cloud.
Whether or not your company is sharing a network with users outside your firewall is a key part that separates public cloud from private cloud. This may or may not mean the servers are on-site, but connectivity is probably done through a VPN connection and there are a lot of encryptions that keep anyone else from accessing the network. Public clouds also have a lot of security, but your company is sharing software, computing or infrastructure with other companies using the same network.
Another key aspect of private cloud is that management is done within the organization itself. This means that if something goes haywire the company has someone to blame within its own ranks rather than has to rely on the provider of the cloud service to fix the issue.
The private cloud platform can also scale on demand, to the degree to which the company can purchase equipment on a whim. It still makes sense from a financial perspective for any company instead of not using a cloud at all and purchasing all software and hardware upfront.

Hybrid Cloud

There is also another category called the hybrid cloud. This is a form of cloud computing where a company may manage its own infrastructure and thus rely on private cloud for IaaS, but at the same time allow this infrastructure to go outside the firewall for other cloud computing tasks such as SaaS. This model has aspects of both private and public cloud in different areas of the company’s operations. Another example of the hybrid cloud, as outlined by SearchCloudComputing, is if a company uses Amazon Simple Storage Service (Amazon S3), which is a public cloud service to store archival data, while it relies on in-house storage infrastructure for customer data being used on a daily basis.

Conclusion

Cloud computing is much more complex and varied than meets the eye at first. The idea isn’t just based on an on demand network with freedom of infrastructure accessibility. There are also both self-hosted private cloud networks running within companies’ own ranks, and companies like Amazon that are embracing the cloud for the public enterprise market. It will be a very interesting in the next couple of years to see how bigger companies embrace the public cloud. They are the most reluctant to make the switch due to the fear of loss of control, security, outages, being tied down to an external network, and other things that these enterprises have to consider when choosing an infrastructure. Cloud computing, both public and private, however will continue to evolve and offer more options for both smaller companies and large enterprises.