Niels Kok (@nielskok5) has written an article about a script to set drain mode for all session hosts via powershell in one #WindowsVirtualDesktop (#WVD) hostpool. This is a script for the ARM release. The fall release CMDLets of WVD uses other CMDlets.

Read it here: https://www.nielskok.tech/windows-virtual-desktop/wvd-set-drain-mode-powershell/