If you are are planning to upgrade your Horizon Connection Server’s OS, there are two different paths. One is using an in-place upgrade of Windows Server that can work (in theory). The second one is decommisioning your connection server and replace with a new one (and repeat if you have more).

The strategy really depends of the size of your environment and how much is production critical.

With a dev or lab environment single server, the in-place OS upgrade could make sense.

But in a production environment with more connection servers in replica, only the second option is safe enough.

Connection Server decomissioning

If your have a multi connection server environment using the native replica, you can remove one connection server and replace with the new one.

Horizon allows you to configure one or more replica Connection Server instances in a Connection Server group. You can disable a Connection Server instance in a group, but the entry for the server persists within the Horizon configuration.

To make the removal permanent, perform these tasks:

1. If needed, reassign the Active Directory schema master and naming master role on the cluster on a different Connection Server.
2. Uninstall the Connection Server instance from the Windows Server computer by running the Connection Server installer.
3. Remove the AD LDS Instance VMwareVDMDS program from the Windows Server computer by running the Add or Remove Programs tool.
   • If the Connection Server belongs to a CPA federation, remove the AD LDS Instance VMwareVDMDSG program from the Windows Server computer by running the Add or Remove Programs tool.
4. Remore the role AD LDS role from Windows Server Manager.
5. Power-off the Connection Server.

On another Connection Server instance, use the vdmadmin command with the -S option to remove the entry for the uninstalled Connection Server instance from the configuration:

vdmadmin -S [-b authentication_arguments] -r -s OLD_CONNECTION_SERVER_NAME

Replace with the new Connection Server

Create a new Windows system with the desidered OS version (like Windows Server 2022) using the same IP address of previous server.

Join this system to the same Active Directory domain of the other connections server and use the same hostname of the previous server. Old AD entry will be replaced by the new system.

Of course, you can use new hostname and/or new IP address, but in this case you need to remove old AD entries and update your load balancer settings.

Install Horizon Connection Server in replica mode and point to an existing connection server. I suggest to install the SAME Horizon version to minimize changes and variables… If you also need to perform an Horizon upgrade, do it after (or before) the upgrade of the OSes.

Check if replication between connection server is fine.