Did the title of this blog entry scare you and make you think, "Why in the world would I do that?" If so, then there is no need to read further. The point of this blog post is not to tell you why you should be doing so, only why some have chosen to do so, and what issues they find themselves dealing with after having done so. If you still think that the idea of moving any of your data center to the cloud is simply ludicrous, you may go back to your regularly scheduled programming.
If the demand for on your company's IT resources is consistent throughout the week and year, then the biggest reason for moving to the cloud really doesn't apply to you. Consider how Amazon Web Services (AWS) got built. They discovered that most of the demand on their company's IT resources came from a few days of the year: Black Friday, Mother's Day, Christmas, etc. The rest of the year, the bulk of their IT resources were going unused. They asked themselves whether there might be other people who had the need for their IT resources when they weren't using them, and AWS was born. It has, of course, grown well beyond the simple desire to sell excess capacity into one of their most profitable business lines.
If your company's IT systems have a demand curve like that, then the public cloud might be for you. Why pay for servers to sit there for an entire year when you can rent them when demand is high and give them back when demand is low? In fact, some companies even rent extra computing capacity by the hour when the demand is high. Imagine being able to scale the capabilities of your data center within minutes in order to meet the increased demand created by a Slashdot article or a viral video. This is the reason to go to the cloud. Then, once the demand goes down, simply give that capacity back.
The challenge for IT people looking to replace portions of their data center with the public cloud is automating it, and making sure that what they automate fits within the budget. While a public cloud vendor can typically scale to whatever demand level you find yourself with, the bill will automatically scale as well. Unless the huge spike in demand is directly related to a huge spike in sales, your CFO might not take kindly to an enormous bill when your video goes viral. Make sure you plan for that ahead of time so you don't end up having to pay a huge and unexpected cost. Perhaps the decision will be made to just let things get slow for a while. After all, that ends up in the news, too. And if you believe all publicity is good publicity, then maybe it wouldn't be such a bad thing.
There are plenty of companies that have replaced all their data centers with the cloud. Netflix is perhaps the most famous company that runs their entire infrastructure in AWS. But they argue that the constant changes in demand for their videos make them a perfect match for such a setup. Make sure the way your customers use your services is consistent with the way the public cloud works, and make sure that your CFO is ready for the bill if and when it happens. That's how to move things into the cloud.