In a traditional data center setup, "every time you add a server, somebody has to walk to a firewall console, set up firewall rules, attach the server to a VLAN, set up load balancing" and do many other tasks, explains Jeff Deacon, cloud computing principal at Verizon Business, a unit of Verizon Communications Inc. that provides managed services. But a private cloud needs little human intervention other than bringing in new computers or storage to keep up with demand. In a cloud environment, there is one console that lets operators set parameters to automate the entire process, rather than requiring IT personnel to log into different consoles for security, networking and server operating system functions.
Another big difference between private clouds and traditional data centers involves IT processes, which probably need to be revamped for a private cloud. Today, for example, to provide computing resources, IT organizations typically have to get budget approvals, discuss the implications with storage, network and server groups, and fill out tons of paperwork. This type of process is in stark contrast to the streamlined, short-duration provisioning done in clouds. The time-to-provision may go from weeks in the traditional data center to minutes in a cloud.
The systems running older applications may need an overhaul too, if they're based on mainframes and proprietary Unix platforms. Most virtualized environments, including private clouds, are geared to run on x86-based systems. Also, in a virtualized environment, you generally don't know exactly where an application is running at any given time. Because most legacy applications are tied to a specific platform, running them in a private cloud will often require re-architecting them.
Divorcing applications from the hardware is a hallmark of clouds, including private clouds. In a traditional data center, you might have 10 servers running billing applications, and five other servers running customer data apps. But with a private cloud, it's not known ahead of time which servers will run which specific applications. The applications run on whichever servers have free cycles at the time the apps need to run.
Private clouds involve two groups of people: the IT operations staff and the business users who want to run applications. A private cloud gives business users the opportunity to quickly provision a server and run an application when they want to, without human intervention.
The IT operations staffers have to make sure that sufficient resources are available for the type of on-demand computing that business users have heard is available with public clouds, and that usually means that the wait for user-requested resources is minutes, not days. Anything short of this, and end users won't be happy.
By the Numbers