One of the questions that is often asked of me as a Cloud Solutions Architect and Consultant is: Why do I need a private cloud? This is a valid question on several levels, but rather than give the usual spiel on 'security' and 'control', I want to delve into a tangible usage scenario where a private cloud makes sense. While this is just one scenario, think about the ways that this can apply to so many more scenarios that are similar or have similar goals and end-states.
There is no question that with AWS, Amazon has stepped forward to provide the de facto public cloud offering, and by proxy, the de facto public cloud API. While many want to be competitors in that space, and generate a lot of hype in trying, there is no valid competition to Amazon AWS today. The infrastructure and API are not of much value to the average person, however. This is where 3rd party developers have stepped in to leverage the infrastructure and API and provide valuable services to everyone. Two great examples of this are Dropbox and Crashplan, who use AWS S3 (Simple Storage Service) to provide cloud storage and backup to end users. Both companies have become wild successes, and each utilizes the power of the AWS API as well as the individual services like EC2 and S3.
Storage has traditionally been the realm of hard drive manufacturers and large storage (SAN) companies, and has almost always been 'on premise.' With the advent of AWS and S3, much more is being done with respect to storage in the cloud. More enterprising storage companies are looking for ways to bridge that gap as customers are eager to consume storage both on premise and in the cloud. One only needs to look to the home storage market to see manufacturers of small home NAS devices offering cloud based storage options, some even offering direct backup to S3. While it is fairly inexpensive to develop technology that will backup small amounts of data to S3, cost becomes prohibitive when the data sets reach into the terabytes or petabytes of data, and require massive amounts of bandwidth to move for testing purposes. This is where a private cloud can help drastically.
In the world of enterprise IT, it is no secret that data is king. Data is the core of any enterprise strategy and both traditional storage companies and Amazon AWS know this. Data is the 'hook' that they have to ensure that leaving their SAN offering or S3 storage repository is both painful and costly. If you are a company looking to develop a technology that integrates with AWS from on premise or sits on AWS entirely, the costs to move large amounts of data or spin up many instances in the cloud for development and testing can get expensive. Furthermore, if you want to test the speed and reliability of your platform in moving data into and out of S3, the bandwidth costs (not to mention restrictions) can be problematic. A private cloud solves these issues by putting a 'public cloud-like' environment on your local LAN. This means that you can develop and test your apps and technology stack at 'line speed' without the added cost for bandwidth and data storage. It may not be practical to test the movement and fidelity of 100TB of data or a petabyte of data into S3 over your ISP connection, but it is perfectly practical to do this on your local LAN.
In a hybrid-cloud scenario, this also gives you the option of encrypting data locally, in your private cloud environment, before it is shipped off to the public cloud. This is huge in terms of offering a secure product or service to end-users who are leery of the public cloud. If your primary focus for your product or service is on premise with only backup (or limited integration with) to the public cloud, it makes even more sense to develop and test on a private cloud.
In summary, if you need to develop any sort of product or service that integrates with the public cloud, and you want to be able to develop and test at local LAN speeds, a private cloud is an excellent choice. Furthermore, if you have large data storage and transport needs, the private cloud becomes the only reasonable solution which gives you the best performance and no additional bandwidth cost. Look to the private cloud for your development and testing needs.