No VMware Tools Support? Reservations, Please.

I've come across some systems that for one reason or another can't run VMware Tools. This can be due to support reasons, an operating system that doesn't officially have VMware support from the version of the hypervisor or family of operating systems, an appliance that is designed to run on a physical system but doesn't offer virtualization support, or it simply won't install on that system without something else going awry. (While this does not happen frequently, usually the vendor or application owner's response is "The application isn't supported yet with virtualization" or worse, I have to explain what virtualization is.)

As an administrator, you'll know if something will or won't work as a virtual machine. Virtual machines are a wonderful way to tuck away previous systems to use as an archive or inquiry-only role. In these situations, VMware Tools is not there to provide the necessary interaction between the guest operating system and the hypervisor.

I've also had some unexplained behavior if resources are moved around on the the host due to a busy compute and memory environment. The workaround in this situation is to assign a reservation. I usually don't use reservations, as they are typically wasted compute and memory resources. But if you must, you can do it both with licensed vSphere and VI3 installations, as well as the free ESXi hypervisor (see Fig. 1).

Figure 1. The resource reservations are shown for both memory and processor categories. (Click image to view larger version.)

If you see the reservation increase (enabled by the expandable option), you know that you have allocated too little and the resource scheduler may increase what is assigned to this category. This can be done for a resource pool, an individual VM or a vApp in vSphere. Again, I only assign reservations when a situation requires it -- lack of VMware Tools is one case where it makes sense.

Do you have systems without VMware Tools? How do you plan on resource allocation beyond the base virtual machine provisioning process? Send me e-mail (preferred) or comment here.

Posted by Rick Vanover on 02/02/2010 at 12:47 PM