Fault Zone

The “Private Cloud” (or lack thereof)

I’ve always enjoyed discovering the use of oxymorons in everyday language; a peculiar turn-of-phrase like “successful failure,” “simple grandeur,” or “comforting chaos” can raise the eyebrow and prompt a smile, all while delivering a potent dose of meaning. These simple demonstrations of irony are quite often delightful, and occasionally brilliant.

Unfortunately, oxymorons are not always intended, and as such, must be held up for further scrutiny. To wit, I give you: the “Private Cloud.”

On the surface, the notion seems innocuous enough. I hear this cloud thing is great, but it’s out there in Internet-land, and that’s scary. So why can’t I get some cloud-like stuff inside of my enterprise and have all the benefits with none of the risks?

The real problem with allowing this linguistic genie to escape its bottle is that the notion of a private cloud, while eye-catching as a marketing term, completely misses the point. Say it with me: there is no private cloud. Let me explain.

When a SaaS (software-as-a-service) company makes the claim that they run software “in the cloud,” they are not just saying that you can connect to their application over the Internet (in fact, some SaaS applications are better served over private network connections like MPLS — more some other time). Serving software from in the cloud also implies:

  1. Economies of scale via shared infrastructure. No given physical host is dedicated to particular customer; instead, all resources are shared across tenants. This way, no capacity goes to waste, requiring far less capital investment.
  2. Load balancing and disaster recovery via massive distribution and redundancy. All server roles are replicated across multiple servers in multiple data centers; there is no single point of failure.
  3. Minimum downtime via coordinated software updates. Software upgrades are performed once for all clients, and are performed in a rolling manner, preventing service interruptions.
  4. Large reduction in ongoing maintenance costs via shared operations staff. Cloud vendors become experts in efficient care and feeding of their purpose-built infrastructures, and can thus pass the savings on to customers.

So what could a “private cloud” possibly be? The meaning of “private” is easy enough to decipher — a desired application would need to run exclusively in a given private data center, and would necessarily be dedicated to the given enterprise’s local base of users. This is not new; many large companies run application server farms for internal use, and to some limited extent they can run multiple applications across these servers, reducing overall costs.

But what about “cloud,” and the benefits it implies? The economies of scale go only so far for a limited application audience, and a single company can only justify so much budget on redundant systems. Further, anyone who has spent significant time dealing with enterprise software upgrades understands the pain these can introduce when managed by local IT staff, even in those exceptional cases wherein nothing goes wrong. Finally, the incredible cost burden of managing an ever-increasing server farm has been enough of a concern to end many large, distributed software projects in the budget office.

There are times when it is perfectly appropriate to invest in a locally-hosted software product; however, be wary of software vendors targeting the “private cloud” with their traditional offerings. Chances are good that you won’t get what a true cloud-based solution can deliver.