Automating Lab Buildouts with XenServer PowerShell – Part 4 Roles, Features, and Other Components

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

Introduction

Creating an automated lab has its benefits, but what about the additional configuration of roles and features after all the servers are built? Building out all of these components can take some time, time that you may not have.

For this reason, AXL has the functionality to add a small subset of additional roles and features to any server that was created. The current roles and features that can be installed and configured with AXL include, Active Directory Domain Services (AD DS), Active Directory Certificate Services (AD CS), and Distributed File System (DFS).

It’s important to note that you can only configure these additional roles and features if the custom ISO you created in part 2 has XenServer Tools in it. If you did not select to put XenServer Tools in the ISO, there will be no way to grab the servers IP address after installation.

Upon completion of server creation, you will be prompted whether or not you want to configure additional roles and features. Upon selecting yes, you will get a prompt as show in Figure 1. If you choose to install any of the additional roles and features, the only requirement is AD DS, as noted by it being automatically checked and grayed out via the component selection form, everything else is optional.

Each of the other roles and features require the server to be part of a domain, which is why AD DS is a requirement. The total additional time of completion will depend on the selected roles and features, each one will take a varying amount of time depending on how large the buildout is.

Figure 1 – Component

AD DS Buildout

Upon selecting to build out additional roles and features, you are required to configure AD DS. The complete configuration includes a mandatory AD DS configuration and an optional User, Group, and OU configuration. I should note that at any time during the configuration of any form you wish to go back and reconfigure something, you can do so by selecting the previous button, if present.

The configuration for AD DS is a lot like the normal configuration you would go through if you were doing it directly on the server, however, there are some other configurations that go along with this form that you would normally do prior to domain creation; notably the IP configuration, as seen in Figure 2. Starting at the top, you will need to configure the local administrator username and password (configured when making the custom ISO), domain name, and safe mode password.

In the next section, you will notice a large list box on the left with all the servers you created in the previous form. Each server will need to be configured with an IP, default gateway, subnet mask, and DNS server(s) and can be done by selecting each server individually from the listbox; the DNS server configuration is important when joining a server to the domain, you will want at least one domain controller IP in the DNS server configuration for proper functionality. As you fill in each of the text boxes for each server, an array will simultaneously be filled in with the information input to allow complete control over the configuration.


Figure 2 – Domain Buildout

Below, you will see a code snippet on how the IP configurations are actually changed.

After all the aforementioned information is filled in, the next thing to configure would be which servers you want to make Domain Controllers. There must be at least one domain controller, if multiples are selected, you can choose which one will be the primary Domain Controller; the first server selected will automatically become the primary, but this can be changed if desired.

Once everything is configured to your liking, you need to validate the configuration by selecting the validate button. This will verify correct syntax for the domain name, safe mode password, IP schemas, and other minor configurations.

Below is a snippet of code outlining the primary Domain Controller promotion process.

No matter what was chosen on the initial component selection screen, after selecting next on the domain buildout form, you will always get the User, Group, OU buildout form if you want to configure any users, groups, or OUs for your environment.

This form is 100% optional and does not require any of the fields to be filled out. If you do not want to configure any users, groups, or OUs, simply just move onto the next form, if any.

However, if you do choose to fill it out, you will notice three different section, each labeled with their intended purpose. Figure 3 depicts what a filled-out form might look like.

Figure 3 – User Group OU Buildout

Each OU added to the structure can be placed under any OU already created and can be as many levels deep as you wish, though I would not recommend any more than 10 levels for any Active Directory structure. For the Users and Groups, you can input the required information and select add, which will add it to the respective list box.

You will notice there is no validate button for this form, that is because the validation is done before any item is added to a list box. This configuration provides the flexibility to allow you to configure any combination of users, groups, OU’s, or none at all.

AD Certificate Services Buildout

Figure 4 – AD CS Buildout

The next form, if this role was chosen from the form in Figure 1, is AD CS. With this form, seen in Figure 4, you have the ability to completely configure a normal AD CS buildout, as well as AD CS Web Enrollment and OCSP Responder.

Each server added to the list box will need to be configured independently, which can be done by selecting each server from the list box and configuring the required fields.

Each field is entirely separate for each server, meaning you can do different configurations for each one, depending on the CA type chosen. Each Server in the list box can either be a root CA or subordinate CA. If you choose to create a subordinate CA, you will have a more limited selection of fields available compared to a root CA configuration.

This is because the subordinate CA gets all of its configuration from the root CA. Below is a snippet of code that is used to promote the specified CAs.

Distributed File System Build

The last form, if chosen to configure the component, is the DFS buildout form. This form allows full configuration of a complete DFS structure, including namespaces, replicated folders, and replication groups. DFS allows for replication of folders and folder contents across multiple servers, this configuration will require at least two servers be chosen for proper replication to take place.

Once the DFS servers are chosen, you need to determine what namespaces you want to create, whether you want to have just one namespace, or split it up for a more complex architecture.

Each DFS folder created in the lower section of the form will need to be in a DFS namespace, specified as DFS root in the form. Each server will get a DFSRoots folder created in the root of the C:\ drive, this will house all of the namespaces created.

Furthermore, each folder created will get created in the DFS root specified; for instance, if you created a DFS root called Common and then created a folder named Backups ­and specified Common as the DFS root, a folder would be created as such, C:\DFSRoots\Common\Backups.

There is an optional parameter for the DFS folder, being the target path. The target path specifies where the DFS folder will point to, if a folder is not specified, it will use the default location in DFSRoots. Using the example before, if you specified a target path of C:\SQL Backups, instead of the DFS folder Backups pointing to C:\DFSRoots\Common\Backups, it gets redirected to C:\SQL Backups when pathing out to the folder.

If you are unfamiliar with DFS, all of these folders live under \\\\. This structure allows for seamless, highly available, and redundant file and folder access, even if one or more servers are down depending on the size of the infrastructure.

Below is a snippet of code used to create the DFS folders. You may notice there are nested Invoke-Commands used for the DFS buildout, this is because the DFSN and DFSR commands would not work when executed remotely directly on the selected servers.

So, as a workaround, I was able to get it working by doing a nested Invoke-Command to essentially run a remote command inside of a remote command. This allowed me to execute the DFSN commands used below on a domain controller from the selected DFS server, the command sequence is as follows, My PC -> DFS Server -> DC. This was very frustrating to figure out because the initial commands gave a very arbitrary and ambiguous error code, but after rigorous testing was finally able to get it to work.

Figure 5 – DFS Buildout

Conclusion

This concludes all segments in this four-part series. We have discussed everything from items needed to begin creating automated labs, how to create a custom ISO for an automated installation, creating VMs rapidly and seamlessly with either default, custom, or blank templates, and finishing it off with how to configure AD DS, AD CS, and DFS all with the AXL tool.

There is a lot of functionality built into AXL and all of it is available on GitHub; you will want to make sure you download not only the PowerShell script, but all the files as well, refer to Part 1 of the series if you want a better understanding of how the files structure should be setup.

I have really enjoyed creating AXL and hope everyone who uses it finds it to be a time saving and useful tool.

Zach Thurmond
IT Consultant
Critical Design Associates

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