Of course, Amazon wasn't alone before the big names jumped in. Joyent, Rackspace, SoftLayer, and others have been around for years; all three also offer some form of hosting (dedicated infrastructure) and the shared infrastructure characteristic of public cloud services. With little fanfare, IBM has been selling public cloud IaaS services as well, although customer engagements always begin with an IBM rep rather than the self-service Web GUI Amazon popularized. That's the way engagements with Verizon acquisition Terremark start, too -- if you want Terremark's VMware-powered Enterprise Cloud, that is. If you're willing to live with less functionality, simply enter a credit card number and fill out a Web form to upload VMs to Terremark's VMware vCloud Express.
IaaS has become a competitive space. Here's a quick look at the new IaaS cloudscape -- and a little about how to choose among the various platforms.
The IaaS shop-a-thonThe basic idea of IaaS is simple: You upload virtual machines and run them remotely. But with many providers, the range of options is huge, from compute to storage to database services to app dev options and more.
And pricing? It's hard to know where to start. You need a very good sense of your basic compute, storage, and networking needs from the outset; otherwise, forget about direct comparisons among IaaS providers. Depending on the provider, you may have a choice of dozens of types of instances: Will a single virtual CPU plus 3.75GB of RAM and 300GB of hard disk be enough for each instance, or do you need more? You want that in 32-bit or 64-bit? And there are potential discounts to consider: Reserving infrastructure resources in advance, for example, can be cheaper than pure pay-as-you-go.
Then there are operating system and bandwidth considerations. Most providers offer Windows as well as Linux and pass along the incremental licensing charge to the customer. You also need to consider incoming and outgoing traffic -- if you're greedy it may cost you a lot, depending on the provider.