"Bare-Iron" Virtualization
Featuring VMware ESXi 4.0 and vSphere

Bare-Iron Virtualization with VMware ESX / ESXi

Mainstream Virtual Machine technology is one of the most exciting technological advancements in computing in recent years. We deploy solutions that make use of VMware ESXi on "bare iron" (i.e., no Operating System required on host machine) and embedded Virtual Machine technology. One feature that is bound to get attention by everyone is that VMware ESXi is a FREE product! Although it may take some expertise to setup, deploy, end enjoy its full potential, it is a very powerful and capable virtualization solution as part of the VMware VSphere® suite of virtualization software and solutions.

VMware ESXi has reached version 4.1 now, as has the corresponding VMware vSphere client. The transition from ESXi / ESX version 4.0 to ESXi / ESXi version 4.1 required a bit more work than the prior version upgrades did. We published a detailed guide to upgrading VMware ESXi 4.0 to ESXi 4.1 on our software and technology blog to help others through this update and transition.

The transition from ESXi / ESX version 3.5 to ESXi / ESX version 4.0 went quite smoothly on our own servers using VMware vSphere Host Update Utility 4.0. We highly recommend this latest release of VMware's bare-iron virtualization solution, as it introduces many much anticipated features and improvements including substantially better high-resolution guest-OS displays (to 1920x1200 and beyond, which is great for software development tasks), and other enterprise class virtualization features.

Hosted vs. Bare-Metal Virtualization

There are two common approaches to virtualization: "hosted" and "bare-metal". Hosted virtualization software runs as an application or "guest" on top of a general-purpose operating system (e.g., MS Windows or Linux). Bare-metal virtualization, like VMware ESXi, interfaces directly with computer hardware, without the need for a host operating system. We deploy VMware ESXi on our Servers (when you desire) in order to provide a high-quality and capable virtualization environment. See our Virtualization Introduction page for a bit more discussion about Hosted vs. Bare-Metal Virtualization.

There are various compelling reasons to use Bare-Metal Virtualization with VMware ESXi; one of those being security. The picture above quickly demonstrates how the hosted/host-based virtualization solution differs from the bare-metal approach, and how the bare-metal hypervisor offers some protection against common security issues.

One rather significant potential savings that can be realized with bare-iron virtualization is a simple one: the cost of an Operating System license for the host machine (as compared to using a "hosted" VM solution where you need that host-system's operating system license). We run VMware ESXi exclusively as our bare-iron virtualization technology on our own powerful high-efficiency servers and high-efficiency workstations, like our custom built 1U SSD-equipped SuperMicro units; no dependency on any proprietary and costly host operating system like Microsoft Windows Server 2003 or Microsoft Windows Server 2008 here!

• One substantial consideration when selecting a virtual solution is what hardware devices (i.e., system devices) the virtualization software will recognize, support, and allow the various hosted virtual machines access to. If you require access to USB devices, like USB printers, scanners, flash drives, cameras, and other USB devices that are typically considered "plug and play" these days, chances are rather good that you will want to implement a hosted solution in order to gain access to those devices.
• Currently, a bare-iron virtual solution like VMware ESXi does not support / allow the hosted virtual machines to access USB devices. By contrast, VMware Workstation has rather robust support for such devices and pass-through (to guest machines) support. UPDATE — JUNE, 2011: the upcoming VMware ESX / ESXi version 5.0 is rumored to include support for host machines to access USB devices and smart-card readers and more. See this blog about VMware ESXi 5.0 Release Features of Interest for more feature previews.