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If you think your business could benefit from a private cloud, you're not alone. But not everyone understands what a private cloud is or when, exactly, a virtual environment becomes a private cloud. The answer, it seems, might be entirely up to you.
So what is a private cloud? I'd describe a private cloud as a host cluster with high availability and Distributed Resource Scheduler turned on, plus a little bit more. Those additional pieces relate to self-service provisioning, or giving others within the enterprise the ability to create their own virtual machines (VMs). A self-service portal, powered by automation and VM templates, removes a big portion of the manual work involved with building new VMs.
Ingredients for a private cloud and self-service portal
Let's assume you already have a virtual environment in place that has load balancing and failover on a host cluster. These technologies are basic, even for small and medium-sized businesses (SMBs) with virtualization needs. Promoting your virtual environment to a private cloud requires just a few extra steps.
VM templates. A self-service portal lets individuals requesting a new VM provision that VM themselves -- starting from a basic configuration. Every virtual platform supports the use of VM templates to accomplish this. Using the same skills you use to create golden images for desktops and laptops, your first job is to create one or more server templates that someone else can automatically provision. The templates should fulfill users' needs without wasting resources.
Resource pools. The scariest notion of self-service is that an empowered end user can create VMs all day long. Given a blank slate, unauthorized VMs are likely to quickly fill up your virtual environment. Place boundaries on end users' actions by creating one or more resource pools. Each hypervisor implements these pools differently, but, in general, these pools designate a maximum quantity of resources (processing, memory, networking and storage) that a self-serving end user can consume.
A user interface for self-service. While managing your virtual environment requires full access to traditional management tools, other users require far less access. Every hypervisor platform comes with options for delivering self-service; some options cost extra, others are free add-ons. Some hypervisor management tools also support a Web-based alternative that an admin can use as a self-service portal for no charge. Spend time researching your options. The wrong tool might make the job more time-consuming than manually building VMs.
A request process. This last ingredient is critically important because without the request process, you've only created an empty space that's waiting for overpopulation. Self-service shouldn't be carte blanche. Your business rules should still determine when a request is appropriate.
Cooking up your private cloud
Once all the ingredients are in place, implementing them involves more than installing a self-service portal (if it is not installed already) and training end users.
Capacity management and performance monitoring become even more important in a self-service environment. Even with well-constructed resource pools in place, an admin must pay careful attention to the supply and demand of computing resources. Plan for the long term to ensure you'll have enough resources on hand to meet future business demands.
With a few good VM templates and the right users, self-service is very useful. It can eliminate a sizeable portion of the manual labor an admin faces every time an end user requests a new VM. Self-service provisioning can also speed up the delivery time of new IT services.
But a private cloud and self-service portal aren't right for all SMBs. The IT needs for many businesses are often met by a host cluster with high availability and active DRS. An admin who regularly provisions and de-provisions VMs for end users will see the greatest benefit of moving to a private cloud.