But Iams says you should plan on managing multiple hypervisors, such as VMware's ESX, Microsoft's Hyper-V, the open-source Xen, and various implementations of the Linux KVM (Kernel-based Virtual Machine). Microsoft can manage Hyper-V virtual servers and some aspects of ESX virtual servers. Other cloud vendors, such as VMware and Red Hat Inc., can also manage virtual machines created by multiple hypervisors. Ideally, you want to control multiple hypervisors from a single interface.
Buy or Build?
The downside of commercial, off-the-shelf tools is that they will likely need to be customized to work with your environment. On the other hand, the downside of rolling your own tools is that your in-house IT group will need to maintain them and make feature enhancements. One alternative to homegrown tools is building mixed-component cloud stacks by acquiring various third-party components and putting them together. The question then becomes: Who do you call when there's a problem?
You could choose to go with a single provider, such as Microsoft or VMware, but that can result in vendor lock-in.
Open-source software -- from the OpenStack project and from vendors such as Abiquo, Cloud.com, Eucalyptus Systems and Red Hat -- is a good choice for building private clouds. The software is essentially free and provides more flexibility than proprietary software licensed on physical CPUs. For example, proprietary software can create difficult licensing issues when migrating virtual machines from host to host.
Each alternative has its pluses and minuses, so weigh your options carefully, because switching gears once you're already under way is expensive and time-consuming. Don't lock yourself into a single vendor's cloud stack. In particular, avoid vendors with cloud stacks that perform well when using only their components. Reserve the option to plug in third-party or homegrown tools.
Here's a sampling of vendors that claim to have tools for building private clouds.
* BMC Software Inc. (Cloud Lifecycle Management)
* CA Inc. (3Tera AppLogic)
* Cisco/EMC/VMware (Vblock)
* Citrix Systems Inc. (Citrix Open Cloud)
* Cloud.com Inc. (CloudStack 2.0)
* Dell Inc. (Virtual Integrated System)
* Enomaly Inc. (Elastic Computing Platform)
* Eucalyptus Systems Inc. (Eucalyptus 2.0)
* Hewlett-Packard Co. (BladeSystem Matrix)
* IBM (CloudBurst)
* NewScale Inc. (NewScale 9)
* Platform Computing Corp. (Platform ISF)
* Tibco Software Inc. (Tibco Silver)
* VMware (vCloud)
Source: Forrester Research Inc., August 2010