It’s no surprise that just about every customer likes the on-demand, rapid scale nature of cloud computing.
More interestingly, we also heard from enterprises with public cloud experience that this was a double-edged sword. Dynamic and on-demand can also mean unpredictable and hard to control. As one customer explained to me, “We have no idea what the credit card bill is going to be at the end of the month, and we have a finite budget”. In other words, dynamic is great if your budget is dynamic too – which isn’t the nature of budgets and finance folk. And this was for one application. Just imagine a situation where an IT department is providing raw compute to many different business units, and wants to delegate administration to them but also stick to a budget.
Fundamentally, the tension between on-demand infrastructure and predictable costs isn’t going to go away anytime soon. But I do believe that the concept of virtual data centers can provide a “Goldilocks” middle ground solution. Within vCloud Datacenter Services from VMware’s partners, enterprises can subscribe to committed VDCs of a given size. The cost of that VDC is fixed and predictable — related to the amount of resources that are now committed. This puts a control boundary on costs, and your service provider can tell you exactly what that will be – so you get predictable spending against your budget.
Within that VDC, you and your user population can run, start and stop as many VMs as you like – truly dynamic self-service. End-users can never run up a massive bill through over-consumption, because they can never consume more resources than the VDC provides (and vCloud Director offers automated policy controls to clean up forgotten VMs). If it turns out you need a bigger or smaller VDC, you open a ticket with your service provider to make that change. So you haven’t had to give up on-demand compute infrastructure, either.
Perhaps not surprisingly, when “cloudy” types gather over drinks this is a source of vigorous debate. Can opening a ticket really be on-demand? Frankly, I don’t think there will ever be agreement on that, but it does provide a useful middle ground: on-demand self-service for VMs within the boundaries of a virtual data center, which can itself be scaled up or down quicker than you can fill out a PO for a new server. It’s something a geek Goldilocks would love—and understand.