Automating Lab Builds with XenServer PowerShell – Part 1 Understanding the Requirements

Part 1 – Understanding the Requirements
Part 2 – Creating a Custom ISO
Part 3 – Unlimited VM Creation
Part 4 – Roles, Features, and Other Components

Part 1 – Understanding the Requirements

Introduction
I was introduced to Citrix products in September of last year and have been working with it every day since. It seems that on a weekly basis I am exploring some new technology or testing an idea that requires a new lab component. I needed a way to automate tasks. My first target was the creation of new Virtual Machines (VMs).

The XenServer hypervisor is my preferred platform. While not particularly difficult, creating new VMs requires manual processes and time including considerations for machine setup, initial Windows installation, configuration, and other mediums.

Purpose
With all of the manual steps required to build a lab multiplied by the number of virtual machines being built repeatedly, I decided to create a tool, called Automated XenServer Labs (“AXL”), that takes the heavy lifting and user interaction involved in creating new VMs out of the equation to allow more time for actual lab work.

AXL leverages the XenServer PowerShell module and allows for a wide range of configurations. The PowerShell module allows for the creation and manipulation of VMs, Pools, Storage, Networks, etc. By utilizing this module, you can obtain greater efficiency and automation when, and if, creating new environments.

You may be wondering at this point how I plan to take away a large part of the user interaction to build a Windows VM, and to you I say, a custom-made ISO. An ISO, for those of you who may not know, is used to install an Operating System (OS).

The custom ISO has an unattended answer file in it, which I will talk about in further parts of this series, that allows for no user interaction during the installation process. AXL automates the creation of the Windows ISO to be used during the unattended OS installation and can also allow you to create an Active Directory domain, set IP addresses and names, and install specific server roles and features.

While AXL will automate the installation and configuration of the VMs, some initial user interaction is required to input how the VMs, ISOs, and Windows Features should be configured.  Given some of this configuration, the overall process will still be much quicker than manually building out all of the VMs.

The following sections will describe the components and infrastructure that are necessary for automating the build of a lab environment using AXL, the files and folders that are required to create the custom ISO, and using it to create a virtually unlimited number of VMs.

Components and Infrastructure
There are multiple items needed for AXL to work, the main items being the infrastructure. The first thing you will need is hardware with XenServer installed since AXL specifically uses the XenServer PowerShell module.

The hardware can be anything from a small form factor Intel NUC, to a custom-built or enterprise-grade server. XenServer can be downloaded for free from Citrix. You will need a My Citrix account to complete the process.

For development, I used the following items, though not all are necessary:

– (3x) Intel NUC Core i7 (XenServer Hosts)
– (1x) Ubiquiti EdgeRouter X
– (1x) HP J9028A ProCurve Switch 1800-24G
– (1x) Endpoint (Can be Windows Server or Windows Desktop OS)

As stated above, not all of these components are necessary since all you really need is a single machine to install XenServer, such as an Intel NUC (or some other server type device) and an endpoint to run AXL from.

NUCs have a very small form factor and are great for lab work, however; RAM and HD/SSD are sold separately, so you will have to account for that in the cost if you plan to use them. I use the switch and router to create different VLANs as needed.

A basic network topology of what I use is shown in Figure 1. I RDP to a VM on one of the NUCs and run AXL.
Explanation of VLAN
Explanation of RDP

The most important thing to note is the endpoint where AXL is running must be able to communicate with the XenServer host(s). This means that proper routing and firewall configurations must be in place prior to using AXL. NOTE: Firewall and routing configurations are outside the scope of this post and will not be covered.

Files and Folder Structure
There are a number of files needed for AXL to function. The files use are posted on GitHub, with the most important being the PowerShell script.

The files needed for the ISO creation process are as follows:

– autounattend.xml
– etfsboot.com
– oscdimg.exe
– Windows ISOs and associated licenses (MSDN, Visual Studio, etc)
– Expanded XenServer Tools (this is optional)

I won’t go in depth on any of these files in this part as they will be discussed in Part 2 of this series.

The only files that are required for the VM creation process is the PowerShell module for XenServer, which is actually a folder. Once you have all the required files and folders, you’ll need to put them either in a folder on the root of the C:\ drive, or in a folder on the Desktop. I would recommend creating a folder just for the PowerShell script and all the necessary files so they are all easily accessible.

The folder structure I use is as follows:

Conclusion
To recap, you will want to get all the required files and folders for AXL and make a suitable folder structure. With the exception of the Windows and XenServer ISOs, all of the files and folders can be downloaded from GitHub.

You will want at least one endpoint (workstation or server) running AXL and one XenServer to host the VMs. With an understanding of the components, files, and folders, you should now have a solid grasp of the overall requirements for using AXL.

And don’t forget to check out Part 2 where the ISO creation process will be discussed in further detail.