Virtualization Tips Update

Using a Modem in a Hyper-V VM

Although modems may be deprecated technology they still have some uses in modern computing (one immediate common reason is for network-based faxing) and therefore we can sometimes find ourselves in situations where we need to use them from a virtual machine.

Unfortunately, this functionality is not built into Hyper-V by default. Theoretically named pipes can be used to get a modem working in a VM but most people who’ve attempted this have come up short. The most time effective solution to this problem in my experience s to purchase a USB modem and connect it to a device that allows you to use USB devices over the network ( is a product I’ve seen many use successfully).

For more Hyper-V tips please visit Virtualization Admin Knowledge Base

Utilities for Planning VM Capacity

One of the biggest uncertainties when planning a server deployment is gauging the necessary hardware to support your software and user load. The equation gets even more convoluted when you have to plan for virtualization as a part of your deployment.

Depending on whether you are using VMWare or Microsoft products there are tools available that can aide in this process. If you are deploying a VMWare based virtualization solution then they offer the vCenter Capacity IQ tool, available here. If you are sticking with a Microsoft Hyper-V based solution you can obtain the Microsoft Assessment and Planning Toolkit for Hyper-V here.

Capacity planning is one of the most important parts of a new server deployment, so the use of these tools is crucial in ensuring you don’t get caught with hardware that won’t get the job done.

For more Virtualization tips please visit Virtualization Admin Knowledge Base

Removing Servers from the Application Virtualization Management Console

The Microsoft App-V management console is quite robust but doesn’t provide an efficient way to remove management servers from the console. There is a method to do this, but it involves deleting all of the servers in the management console and adding back only those you want.  

In order to do this, go to the Start Menu and launch mmc.exe. From the File drop-down menu, click Add/Remove snap-in, click the Add button, and select the Application Virtualization Management Console. Supply the host name of one of the servers, click OK, click Close, and click OK again. Continue adding the additional servers you want to manage, excluding the one you wish to remove. When you have finished this process, choose File from the drop-down menu, click Save, and overwrite the sftMMC.msc file located in the C:\Program Files\Microsoft System Center App Virtualization Management Server\App Virtualization Management Console directory.

For more Hyper-V tips please visit Virtualization Admin Knowledge Base

Performing Windows Updates on Offline Hyper-V Virtual Machines

Given the current state of information security performing windows updates should be one of the top items on any network administrators list. In many environments where virtualization is widely deployed it is common for sysadmins to maintain base VHD files for rapid server deployment. One of the more cumbersome tasks for these sysadmins are constantly deploying new updates to the VHD files.

The Offline Virtual Machine Servicing Tools allow you to perform updates (and other tasks) to VMs that are not currently turned on. This free download from Microsoft will allow you to create scheduled tasks which perform scripted actions on VM’s by booting them up silently, performing the action, and shutting them back down.

You can read more about the Offline Virtual Machine Servicing Tool here.

For more Hyper-V tips please visit Virtualization Admin Knowledge Base

Hyper-V Command Line Management Tools

The Hyper-V management interface is quite extensive, but Hyper-V doesn’t come with a great deal of functionality out of the box when it comes to managing it through the command line. CodePlex now has a downloadable package which contains over 80 PowerShell commands for administration of Hyper-V. Some of the things you can do with these commands include:

  • Connecting to VMs
  • Manipulating Machine States
  • Backing up and Snapshotting VMs
  • Manipulating Disks, Network Interfaces, and VHD Files

You can download this package here and view a video overview of its features on Microsoft TechNet here.

For more Hyper-V tips please visit Virtualization Admin Knowledge Base

Booting a VMWare VM from CD, USB, or the Network

It may seem like a bit of stretch as to why someone would need to boot a VM to anything other than the virtual hard disk, but that’s only because you’ve never run into a situation where you’ve had to do it before. I ran into this problem myself a few weeks ago and I found myself wondering if it’s even possible to do this. On a physical machine you’d simple boot into the BIOS and change the boot order for the system you’re working on. Most newer systems even have a button you can press during startup that will give you a simple boot device selection option as well.

After a bit of research, I found that you can indeed boot a VM from a CD or USB device. As a matter of fact, VM’s have their own BIOS that you can access. It is a bit tricky to access these menus because VM’s typically boot past this screen very quickly, but it can be done. In order to access the boot menu for a VM you must power on the VM and immediately click inside the VM window and tap the escape key as soon as you see the VMWare splash screen. If done in time, you will see a boot device selection prompt, allowing you to boot to an alternate device. Also, pressing F2 during this time period will allow for access to the virtual BIOS, allowing you to permanently change the boot order of the VM.

If you are having trouble accessing these screens due to how small the time window is, you can increase this time window by editing the bios.BootDelay value in the VMX file associated with the VM. This value is in milliseconds and can be increased to as long as you like to ensure you have time to access the BIOS and boot screen menus.

For more VMware tips please visit Virtualization Admin Knowledge Base.

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