This article was first published on SearchServerVirtualization.TechTarget.com.

The .NET Advantage

In the first article in this series, Automating Virtual Server Using VBScript, I provided an overview of Virtual Server’s COM API. If you’re unfamiliar with the object model, I recommend you read that article before continuing with this one. To get started quickly, I presented examples in VBScript format. While this was a simple way to get started, many developers and systems administrators will want to use the features of a type-safe, compiled language for their production automation needs. In this article, I’ll walk through the process of getting started with Virtual Server’s COM API using Visual Studio .NET. And, I’ll provide code samples in both C# and Visual Basic.NET.

Creating a .NET Application

In order to make the most of the topics in this article, you’ll need to be familiar with developing simple .NET applications using Visual Studio. If you don’t consider yourself at least a closet developer, I recommend you stick with using VBScript (at least to being with). If you’d like more information about Microsoft’s .NET development technologies, a great starting place is the Microsoft Developer Network (MSDN) .NET site at http://msdn.microsoft.com/net.

There’s one important requirement that you’ll need to keep in mind when automating Virtual Server using .NET: You must have your COM security settings configured so that your applications will be able to access either the local instance of Virtual Server, or an instance running on another computer. Details related to doing this programmatically are covered in the Virtual Server Programmer’s Guide (a help file that’s automatically installed with Virtual Server). While you’re there, be sure to read details related to threading recommendations.

OK, now that we have the preliminary information out of the way, let’s get started by looking at code that can be using in a C# or VB.NET application. These examples can be used in any type of .NET application, including Windows Forms applications, ASP.NET web applications, command-line applications, and Windows Services.

Checking Your References

Once you’ve created a new .NET project, you’ll need to add a reference to the Virtual Server 2005 R2 Type Library. If you’re using Visual Studio, you can easily to this by clicking on Project à Add Reference, and then selecting the COM tab (see Figure 1). As long as Virtual Server is installed and registered on the local machine, you should see the type library listed.

Figure 1: Adding a reference to the “Virtual Server 2005 R2 Type Library” COM object.

Since the type library is a COM object (as opposed to a .NET-based “managed code” object), Visual Studio will automatically create a COM interoperability layer. The bottom line is that you’ll now be able to access the API by adding one of the following lines to your source code (I’ll use the convention of presenting Visual Basic.NET code samples first, followed by C#):

Imports Microsoft.VirtualServer.Interop ‘Visual Basic Example

using Microsoft.VirtualServer.Interop; ‘ C# Example

Connecting to Virtual Server

Most commonly, you’ll start writing your code by creating a Virtual Server object. Here are some code samples for connecting to the local instance of the Virtual Server service:

‘ Visual Basic Example

Dim objVirtualServer As VMVirtualServer

objVirtualServer = New VMVirtualServer

‘C# Example

VMVirtualServer objVirtualServer;

objVirtualServer = new VMVirtualServer();

You’re now free to start working with the properties and methods of the Virtual Server object. To get more details (as well as details about connecting to remote instances of Virtual Server), see the Virtual Server Programmer’s Guide.

Working with Virtual Machines

The most common next step in typical Virtual Server automation code will be to create an object that references a specific virtual machine. This process is easy enough and can be done in a couple of different ways. First, if you know the name of the VM for which you want to create an object, you can simply use the .FindVirtualMachine() method of the Virtual Server object that you’ve created (just provide the name of the VM as a string argument).

If you want to loop through all of the VMs on a particular instance of Virtual Server, you can simply iterate through the .VirtualMachines collection (a property of the Virtual Server object itself). One item will be returned for each VM that is attached to the host. Once you have a reference to a particular VM, you can access properties of the VM object to get and set properties such as the amount of physical memory that’s allocated. And, you can use methods to perform operations such as starting and stopping VMs, and adding and removing virtual hardware. We’ll focus on those topics in later articles in this series.

Looking to the Future

So far, we’ve focused on the first steps that are required to get started with building a basic Virtual Server automation application using .NET. Just as a quick example, the process for building a Windows forms application that performs some of the same operations as Virtual Server’s built-in admin tools can be quick and easy. While it’s not exactly a state-of-the-art example of coding finesse, I created a simple but functional demonstration application (shown in Figure 2) in under an hour. And, I chose not to use my favorite .NET language (I’ll let you guess which one that is).

Figure 2: A simple Virtual Server automation application.

The total functional portion of the source code is somewhere around 200 lines (you can download the Visual Studio project from my web site at http://AnilDesai.net). Note that the source code is provided as-is, and it’s only provided as an example – it most certainly isn’t production-quality code.

Update: You can now download the source code directly using the following link: VirtualServerTestApp (Anil Desai).  The file includes a zip file with a Visual Studio 2008 project.  Be sure to see the earlier posts in this series to determine the pre-requisites for running the application.

Building on the Foundation

In this and the previous article, I’ve set the stage for performing more useful tasks. You should now have the ability to connect to an instance of Virtual Server and to create an object for a virtual machine. In the next several articles, I’ll provide details for managing virtual machines, working with virtual hard disks, and configuring virtual networks. We’re just getting warmed up, so stay tuned!

This article was first published on SearchServerVirtualization.TechTarget.com.

Series Introduction

Among the many benefits of deploying virtualization technology is the ability to better manage complex environments. When implemented correctly, it’s often easier to manage virtual machines than it is to keep track of physical ones. But what happens when you end up with a large number of VMs. Organizations that start by dabbling in virtualization often find that the number of virtualization hosts and guest OS’s can quickly get out-of-hand. Add to that the fact that virtualization management tools are still evolving, and you can end up with quite a challenge for systems administrators.

When dealing with physical servers, many IT pros and end-users have found ways to use automated methods of handling otherwise tedious tasks. For example, performing backups and deploying operating system updates are generally done manually in only the smallest of environments.

When it comes managing Microsoft Virtual Server VMs, there’s a readily available method for automation. In this series of articles, Automating Virtual Server, I’ll present details and examples of how you can programmatically manage your VMs. Code samples will be provided in VBScript, Visual Basic .NET, and C# syntax. Some experience with scripting and application development is assumed, but I’ll provide links to relevant information if you need to get up to speed. Overall, I think you’ll find that the process is fairly easy and straight-forward.

Automating Virtualization

If you’re a systems administrator or developer that’s faced with managing a large number of virtual machines, there’s a good chance that you find yourself wishing for a robot that could handle some of the more mundane tasks. While building such a device is more than could be covered in a single article, the focus here is to demonstrate how you can create scripts for performing routine tasks in Virtual Server. We’ll begin by using the VBScript language in this article, since it’s the easiest way to get up and running. In later articles, I’ll provide code samples in .NET languages (C# and Visual Basic.NET).

Virtual Server’s COM API

One of the built-in features of Microsoft Virtual Server is a fully-documented Component Object Model (COM) API. By connecting to this API, you can perform pretty much any task that can be carried out manually using Virtual Server’s built-in tools. In fact, the Virtual Server Administration Web Site itself is simply a web-based user interface that connects to the COM API behind the scenes.

The basic structure of the COM API is based on collections. Figure 1 provides an overview of the some of the most commonly-used ones. The figure is not a complete object model, and the full details can be found in the Virtual Server Programmer’s Guide (a help file that’s automatically installed with the product). The Programmer’s Guide includes details about all of the objects that are available, along with a list of properties, methods and enumeration constants. If you’re doing more than basic scripting, you’ll probably find yourself referring to that file often.

Figure 1: An overview of the Virtual Server COM object model

Getting Started with VBScript

It’s beyond the scope of this article to cover the details of the VBScript language. If you’re not familiar with it, some good starting points for more information are the Microsoft Developer Network (MSDN) Scripting site (http://msdn.microsoft.com/scripting) and the Microsoft TechNet Script Center (http://www.microsoft.com/technet/scriptcenter).

VBScript is based on the Visual Basic language syntax, and it’s a very simple language for getting started with automation. The language is not case-sensitive and it provides for automatic data type conversions. These are two “features” that can help get you up and running quickly (though they’re not good practices when writing production applications).

Another advantage of writing VBScript code is that there’s no requirement for a development environment: Just use your favorite text editor. In most cases, you can copy and paste the code in this article and use it directly on a Windows computer that’s running Virtual Server. OK, let’s get started.

Connecting to Virtual Server

Generally, the first programmatic step you’ll take when creating a new VBScript file for automating Virtual Server is to create a new object that attaches to the COM API. The following statement takes care of this:

Set objVirtualServer = CreateObject(“VirtualServer.Application”)

As long as the Virtual Server product is installed on the local computer, this script should run as-is. By default, this will connect to the instance of Virtual Server that is running on the local machine. If you want to connect to an instance of Virtual Server that’s running on a remote computer, you can use a link such as the following:

Set objVirtualServer = CreateObject(“VirtualServer.Application”,”RemoteServerName”)

Note that you’ll need to have the appropriate security settings and configuration to be able to remotely connect to a COM object (you can get details on these topics using the links provided earlier).

Let’s prove that everything’s working by adding the following two lines to get some information about the local Virtual Server instance:

WScript.Echo “Server Name: “ & objVirtualServer.Name

WScript.Echo “Server Uptime (sec): “ & objVirtualServer.Uptime

Now, the script will output the name of the instance (which should be the same as the machine name), along with the number of seconds that the Virtual Server service has been running. We did this by accessing properties of our “objVirtualServer” object. You can use other methods and properties of the Virtual Server object to perform tasks such as programmatically creating virtual hard disks and changing server settings.

Working with Virtual Machines

Many of the most useful scripts you’ll write will for performing tasks with Virtual Server VMs. You do this by creating a virtual machine object and then setting it equal to a particular VM. If you know the name of a particular VM, you can use the following syntax:

Set objVirtualServer = CreateObject(“VirtualServer.Application”)

objVirtualMachine = objVirtualServer.FindVirtualMachine(“Windows XP SP2”)

First, you create a Virtual Server object (as we did in the previous section), and then you use its find method to create a virtual machine object. What if you don’t know the name of the VM you want to access? You can easily loop through the VMs in the Virtual Server object’s “VirtualMachines” collection. Here’s a sample that outputs the name of each VM on the server:

Set objVirtualServer = CreateObject(“VirtualServer.Application”)

For Each objVirtualMachine in objVirtualServer.VirtualMachines

WScript.Echo(“Name of VM: “) & objVirtualMachine.Name

Next

Once you have a “handle” to a virtual machine, you can access and modify its properties. One commonly-used function is to determine the amount of memory attached to a VM:

WScript.Echo “VM Memory: “ & objVirtualMachine.Memory

Of course, you can perform useful tasks like starting or stopping the VM and managing the virtual hardware configuration (those are topics that we’ll cover in later articles in this series).

The End of the Beginning

In this article, I provided a few simple lines of VBScript code that allowed you to connect to Virtual Server and to work with VMs. Admittedly, we haven’t done anything that’s useful in a practical sense just yet. The goal of this article was to lay the foundation for getting started with automation. Next in the series: Automating Virtual Server using .NET.