The help has very nice documentation on starting OA as a service on either Windows or Linux. see: help→Installation→Windows→WinCC OA as service The concept is this, setup pmon as a service, and he will start all of the managers you have specified.
The problem comes when you want to start a UI on the same computer. You can't start a UI as a service, there exists no graphics yet. Someone must login, or autologin to display a graphics process.
The solution is to start a UI in the startup group in windows, or as a symbolic link in linux. The trick is to know what properties you need for this. Here is an example for windows, it will be similar for linux.
shortcut for windows:
C:\Siemens\Automation\WinCC_OA\3.16\bin\WCCOAui.exe -currentproj -p vision/login.pnl -menuBar -iconBar -style fusion
If you are using a touch screen, add -touch to the list.
The trick is: -currentproj That tells the manager to attach to the project already running. You don't have to specify the project folder, the event manager, the data manager, or any of that stuff. No need for Desktop UI, etc. Just like you started it in pmon.
BONUS: now that you have the system started, how to properly shut down a UI? Most of the time we just click the X in the corner, but there is a better way that takes into account complex architectures and new security methods. Look at this function: STD_CloseUis(); You may need the corresponding #uses for that library.