Conflicts of Interest: MomentumSI consults with organizations on how to select private clouds, install/configure them, monitor, manage, govern and secure them. Transcend Computing provides software that makes the private cloud run more like Amazon. Each company does a significant amount of work in public cloud. We love both public and private clouds.
My day-to-day Experience: I have teams of consultants and engineers who use private cloud and public cloud on every assignment. They have done so for years. Cloud is their default deployment model. Several of my younger team members have never worked with physical servers/disks/network devices - they only know IaaS/PaaS. Team members switch between public and private clouds like they're switching from a pen to a pencil. They don't think twice about it - they just do it. The reasons why they select one over the other are commonsense to them (and anyone who has access to both):
- They run elastic/bursty jobs in the public cloud
- Most new production applications are run in the public cloud because there is built in disaster recovery, elastic scaling and a global footprint: Availability Zones, Regions, etc.
- Pre-production staging environments are done in the public cloud because we want it to mirror the production architecture.
- Most of our legacy COTS applications have been moved to the private cloud. We watch them closely, optimize their environments when needed and avoid violating the license agreements which often prohibit their execution in a public cloud.
- Most dev/test is done in our private clouds. We run Eucalytpus, OpenStack and CloudStack. Most companies wouldn't do this, but we do given the nature of our consulting. Developers prefer private clouds when they want:
- Low latency access to their cloud (for themselves or other applications)
- Low level probing that filters out multi-tenant noisy-neighbors
- Constant booting of a machine (fast and cheap)
- More choice in the cloud hardware configuration (Amazon is getting there, but still has a long way to go...)
- We see more experimentation being done on the private cloud (fixed/sunk costs). Most team members are keenly aware of the large public cloud bills that they've generated.
The reasons why a person might use one or the other are in some ways irrelevant. The fact is, they do. I'm proposing the following:
"When I.T. staff are given access to a public and a private cloud, they will use both. Either way, they will get their work done faster and ultimately save their employer money in labor and asset costs."I had a real hard time swallowing Jason's analysis that clouds are only good when you rent them from a third party like Amazon or Rackspace. Using the vehicle analogy, I believe that it's OK to own your car and to rent other vehicles when needed (e.g., boats, RV's, taxi-cabs, vacation bikes, jet ski's, limos, and so on). It's not an all-or-nothing proposition.
The one thing I want to leave you with is this: I.T. staff will use both - and they'll figure out when to use each. They're not dumb. They don't blindly listen to bloggers, authors, analysts or tweeters. Give them access and let them do what you pay them to do. Empower them.