OBAS installation on a physical server is possible.
Even it's strongly recommended that you deploy OBAS into Virtuozzo Containers container, installation on a physical server is also possible.
Verify the server where you are going to install OBAS meets the Hardware And Software Requirements. Refer to the chapter "If you want to install Parallels Business Automation - Standard on the physical server" of the OBAS Installation Guide for the installation instructions.
Please note: since there is no HWID for a physical server, OBAS license key should be switched to Lease without HWID binding. Option HWID binding cannot be disabled on perpetual (purchased) licenses. Please contact your Sales Representative for the questions about license key update.