There are a number of requirements to contemplate even before the infrastructure needs of the virtual desktops themselves are considered. These include, but are not limited to, the following:

• OS requirements for both vSphere and Horizon components
• Database requirements for vCenter Server, Horizon Composer, and Horizon Connection Server
• Required Microsoft infrastructure services and components

VMware Horizon requires Microsoft AD to support the virtual desktop infrastructure. VMware Horizon supports all AD domain functional levels, starting with Windows 2003 up to Windows 2016.

Horizon also requires Domain Name System (DNS) servers that can resolve requests for the standard Service Record (SRV) and Resource Record (RR) DNS entries. Incomplete or inaccurate DNS entries can lead to issues with tasks, such as virtual desktop deployment and user authentication.

Dynamic Host Configuration Protocol (DHCP) servers are required in the Horizon environment to provide Internet Protocol (IP) addresses to the virtual desktops. In situations where the virtual desktops cannot self-register the IP addresses that they have been assigned, the DHCP server should be configured to register the entries with a DNS server that is accessible by the Horizon Connection Server.

The following table shows which 64-bit non-Core Microsoft Windows Server OSes are supported for the each of the different software packages that comprise a Horizon infrastructure. App Volumes host OS requirements will be outlined separately in Chapter 11, Implementing App Volumes:

While VMware vCenter and the different Horizon servers support a number of different Windows OSes, use of the newest supported version is recommended to ensure that the servers will not be impacted by any changes in OS support by Microsoft. Additionally, you never know when vSphere or Horizon itself will end support for older OSes, which would impact your ability to perform in-place upgrades.

As Horizon Composer supports only Windows Server 2008 R2 SP1, 2012 R2, and 2016, any Horizon installation that plans on deploying linked-clone desktops and installing Composer directly on the vCenter Server will need to choose that specific version of Windows. Refer to the VMware document Horizon 7 Installation (https://docs.vmware.com/en/VMware-Horizon-7/index.html) for updated information regarding which Windows OSes are supported.

The following list shows which database types are supported for the core components of a Horizon infrastructure, which includes the Horizon Connection Server and Horizon Composer. Unless otherwise noted, both 32-bit and 64-bit versions of the specified database platform are supported. Database platforms that support some, but not all, of the components will not be listed. App Volumes database requirements will be outlined separately in Chapter 11, Implementing App Volumes. The databases are as follows:

• Microsoft SQL Server 2017 (Standard and Enterprise; 64-bit is the only version available)
• Microsoft SQL Server 2016 (Standard and Enterprise; through SP1 and 64-bit only)
• Microsoft SQL Server 2014 (Standard and Enterprise; SP1)
• Microsoft SQL Server 2012 (Express, Standard, and Enterprise; 64-bit and SP3 only)
• Microsoft SQL Server 2008 R2 (Express, Standard, and 64-bit Enterprise; SP3)
• Oracle 12C Standard Edition, Release 2 (12.2.0.1.0) - 64-bit

For VMware Horizon, visit the product installation guide (https://docs.vmware.com/en/VMware-Horizon-7/index.html) for updated information regarding which databases are supported.

VMware Horizon supports multiple versions of vSphere. The purchase of Horizon licenses entitles users to use the latest supported version of both vSphere and vCenter Servers, although support is maintained for some older versions due to restrictions that some organizations may be under.

The following versions of vSphere are supported by VMware Horizon:

• vSphere 6.7.0
• vSphere 6.5.0, 6.5 U1, or 6.5 U2
• vSphere 6.0 (Update 1 or newer is required to support the latest Horizon features; Update 2 or newer is required to support VSAN 6.2)
• vSphere 5.5 (Update 3b or newer recommended; SSLv3 must be re-enabled as described in VMware KB article 2139396) (https://kb.vmware.com/s/article/2139396)

Consult the VMware Product Interoperability Matrices for an updated list of the supported versions of vSphere and vCenter Servers. Supporting earlier versions of vSphere and vCenter Servers is important for customers who are already running earlier versions of either software platform, and cannot, or will not, upgrade for some reason. Even with this support, the use of dedicated ESXi servers and vCenter Servers for your Horizon environment is recommended to ensure that all the latest Horizon features are supported.

There are multiple Horizon features that are supported only if certain other prerequisites are met. Examples of these vSphere version-dependent features include the following:

• vSphere 6 is required to use VMware vSAN, or Windows 10 as a desktop OS
• Prior to vSphere 6, the vCenter Server Appliance could not support the maximum number of desktops that can be deployed in a single Horizon Pod
• Some virtual desktop graphics acceleration technologies, such as NVDIA GRID Tesla processor-based server cards (https://www.nvidia.com/en-us/design-visualization/technologies/virtual-gpu/), require vSphere 6 or newer.

A complete list of Horizon features that require specific versions of vSphere or vCenter Server may be found in VMware document Horizon 7 Installation (https://docs.vmware.com/en/VMware-Horizon-7/index.html) or the Horizon 7 Release Notes (https://docs.vmware.com/en/VMware-Horizon-7/7.6/rn/horizon-76-view-release-notes.html) that accompany each release of the Horizon platform.

The VMware Horizon Agent supports multiple versions of the Microsoft Windows desktop OS and Microsoft Windows (RDS) Server. The following table outlines which Windows OSes are currently supported.

To obtain current information about which desktop OSes and Microsoft RDS server versions are supported, please refer to VMware KB articles 2149393 (https://kb.vmware.com/s/article/2149393), 2150305 (https://kb.vmware.com/s/article/2150305), and 2150295 (https://kb.vmware.com/s/article/2150295).