What is Citrix Provisioning (PVS)

Citrix Provisioning Services (PVS) is a key technology within Citrix's virtualization platform that simplifies the management of virtual desktop infrastructure (VDI) and server farms.

Citrix Provisioning Services allows multiple machines to boot and run from a single shared disk image, known as a vDisk. This means that instead of managing separate images for each machine, you can manage a single master image and stream it to multiple virtual or physical machines on demand.

Citrix Provisioning Services Architecture

A Citrix Provisioning Services farm represents the top level of the Provisioning Services infrastructure. A farm includes all the components that make up the Provisioning Services deployment. These components include:

• Citrix Provisioning Server
• SQL Database
• Citrix License Server
• Local and network-shared storage
• Collections of target devices.

Why should you run PVS on Windows Core Server?

Running Citrix Provisioning Services (PVS) on Windows Server Core offers several benefits, particularly regarding security, performance, and resource efficiency. Windows Server Core is a minimalistic version of Windows Server that lacks a traditional graphical user interface (GUI), which makes it ideal for certain server roles, including PVS. Advantages include:

1. Reduced Resource Overhead

• Lower Resource Consumption: Windows Server Core uses fewer system resources (CPU, memory, and disk space) compared to the full GUI version. Since PVS servers primarily focus on provisioning and streaming data over the network, the reduced overhead allows more system resources to be dedicated to PVS tasks, improving performance.
• Faster Boot Times: With fewer services and processes running in the background, the server boots up faster and responds more efficiently.

2. Improved Security

• Smaller Attack Surface: Since Windows Server Core only includes essential components needed to run server roles and services, it has a significantly smaller attack surface compared to a full Windows Server with a GUI. This is critical for security-sensitive environments because fewer components mean fewer potential vulnerabilities.
• Fewer Patches: With fewer features and services installed, there are fewer updates and patches to install, reducing maintenance time and minimizing potential downtime due to patching.

3. Better Performance and Stability

• Optimized for Specific Workloads: Windows Server Core is designed to run specific server roles with fewer background services, leading to more efficient CPU and memory usage. This can be particularly beneficial in high-performance environments where streaming large amounts of data (like vDisks) is a priority.
• Less Risk of Conflicts: Since Server Core is streamlined, there is less chance of conflicting software or services that can affect PVS performance. The stripped-down nature of Server Core reduces the chances of stability issues related to GUI-based components or unnecessary background services.

4. Simplified Maintenance

• Less Frequent Reboots: Because there are fewer components and fewer updates, there’s less need to reboot the server after applying patches or updates. This results in more uptime for your PVS environment.
• Easier to Automate: Since Server Core is typically managed through PowerShell or remote management tools (like Windows Admin Center), it can be easily automated and scripted, allowing for streamlined administration and monitoring in larger environments.

5. Smaller Footprint in Virtualized Environments

• Efficient Use of Virtualization Resources: If PVS runs in a virtualized environment (e.g., on Hyper-V or VMware), Windows Server Core requires fewer virtual resources (CPU, RAM, storage). This leads to better consolidation ratios and higher efficiency when running multiple instances on a hypervisor.
• Faster VM Cloning: With a smaller OS footprint, creating or cloning VMs for PVS servers becomes faster and consumes less disk space.

6. Compliance and Best Practices

• Alignment with Industry Best Practices: Many organizations are adopting Windows Server Core as part of their security and efficiency best practices, especially in data centers where minimizing attack surfaces and resource use is critical.
• Long-Term Strategy: Microsoft is increasingly promoting Server Core as the preferred option for server infrastructure, making it a future-proof choice for organizations aligning with Microsoft’s roadmap.

7. Remote Management

• PowerShell and Remote Tools: Windows Server Core is primarily managed through PowerShell, remote administration tools, or tools like Windows Admin Center. This aligns well with modern IT practices of remote server management, making it more efficient for larger environments where servers are distributed across different locations or data centers.

8. Reduced Storage Requirements

• Smaller Disk Footprint: With fewer components installed, Windows Server Core requires significantly less disk space. This can benefit PVS servers, which may need to store multiple vDisks. The saved storage space can be allocated to vDisk storage or write cache locations instead.

Running Citrix PVS on Windows Server Core is an optimal choice if you’re looking for improved performance, enhanced security, and reduced overhead. Server Core’s smaller footprint, reduced attack surface, and fewer updates complement the PVS environment, allowing for better resource utilization and a more secure, stable deployment.

PVS server support for Windows Server Core

With this feature, you can now install Citrix Provisioning servers on the system running Windows Server Core. The Server Core option is a minimal installation instead of the Server with Desktop Experience installation. The Windows Server core reduces the potential attack surface to critical infrastructure.

 The benefits of using this feature are:

• Enhanced security for the Citrix Provisioning Servers.
• Reduced cost because you can use a smaller VM.

 The current limitations of this feature are:

• You cannot perform a BDM update using the Citrix Provisioning Console (which will be released in versions 2411 and 2402 CU2).

Deployment

Here are the detailed steps to deploy the Windows Core Server with PVS.

Prerequisites:

1. Windows Server Core: Ensure Windows Core is installed and up to date.
2. Administrative access: You must log in as an Administrator.
3. Citrix PVS Software: Download Citrix Provisioning Services from the official Citrix website. Ensure that the Citrix Provisioning Server installation files are available on your server or in a network location.
4. Ensure the necessary roles and features are installed on Windows Server Core, such as `NetFramework,` `Remote Desktop Services,` and `Failover Clustering` (if using a cluster).
5. The Windows Server should be joined to your domain, and the service account for Citrix PVS should have appropriate permissions.
6. Make sure the SQL Server (for the PVS database) is installed and accessible.

Installation

Server configuration:

1. Network Configuration:
   • Configure the network parameters (IP address, Subnet mask, Gateway, DNS).

2. Join Active Directory Domain and rename server:

Prerequisites installation:

1. 1. Install Windows Features:

Run the following PowerShell Command:

Install-WindowsFeature NET-Framework-Core, NET-Framework-45-Features, RSAT-AD-PowerShell

1. 2. Download and install latest Window Updates:

1. 3. Install Citrix Provisioning Services :

Note: The installer UI is fine on the core. You could also mount the ISO and run the installers directly if you want to automate. However, using Windows Core Server, running the install with command line is the preferred way to do it.

• Map the ISO to the server
• In PowerShell, enter the following command:

D:\Server\PVS_Server_x64.exe /s /v” /qn”

Note: The server will reboot during the installation.

Post-Installation tasks

Configure PVS Server

Note: Whilst the configuration wizard can be run interactively, we expect people to run it in silent mode with an answer file.

Details can be found here: https://docs.citrix.com/en-us/provisioning/7-15/install/silent-config-wizard.html

Here is an example of an answer file:

Ensure the configwizard.ans file is in the “C:\ProgramData\Citrix\Provisioning Services” folder and run configwizard.exe /a.

Note: The command needs to be executed logged as a user with access to the DB Server. In our example, domain admin was used.

Deploy PVS Console

Note: The console, which is MMC-based, cannot be run on Core. So, you must install and run it on a separate non-core system.

When the console is installed on a non-core computer, you can open it, connect to the PVS on Windows Core Server, and manage your PVS like a GUI one.