How to get Sikuli working in headless mode
I got SikuliX working in a true headless mode in GCE with a Windows 2016 client system. It takes some duct tape and other Rube Goldberg contraptions to work, but it can be done.
The issue is that, for GCE (and probably AWS and other cloud environment Windows clients), you don't have a virtual video adapter and display, so, unless there's an open RDP connection to the client, it doesn't have a screen, and SikuliX/OpenCV will get a 1024x768 black desktop, and fail.
So, the question is, how to create an RDP connection without having an actual screen anywhere. I did this using Xvfb (X Windows virtual frame buffer). This does require a second VM, though. Xvfb runs on Linux. The other piece of the puzzle is xfreerdp 2.0. The 2.x version is required for compatibility with recent versions of Windows. 1.x is included with some Linux distros; 2.x may need to be built from sources, depending on what flavor Linux you're using. I'm using CentOS, which did require me to build my own.
The commands to establish the headless RDP session, once the pieces are in place, look something like this:
/usr/bin/Xvfb :0 -screen 0 1920x1080x24 &
export DISPLAY=:0.0
/usr/local/bin/xfreerdp /size:1920x1080 /u:[WindowsUser] /p:"[WindowsPassword]" /v:[WindowsTarget]
In our environment we automated this as part of the build job kicked off by Jenkins. For this to work under the Jenkins slave, it was also necessary to run the Jenkins slave as a user process, rather than a service... this can be accomplished by enabling auto admin login and setting the slave launch script as a run (on logon) command.
I successfully got sikuli running in headless mode (no physical monitor connected)
Ubuntu: check Xvfb.
Windows: install display driver on the machine (to be headless) from virtualbox guest additions display drivers and use TightVNC to remotely set resolution from another machine.
Detailed steps for windows 7
Assume that:
- Machine A: to be headless machine, windows 7, with vnc server ready (e.g. TightVNC server installed and waiting for connections).
- Machine B: will be used to remotely setup the virtual display driver on machine A.
steps:
- Download virtualbox guest additions iso file on Machine A from here (for latest version check latest version here and download VBoxGuestAdditions_x.y.z.iso)
- Extract iso file (possibly with winrar) into a directory (let us call it folder D)
- using command prompt cd to D folder
Driver extraction
-To extract the 32-bit drivers to "C:\Drivers", do the following:
- VBoxWindowsAdditions-x86 /extract /D=C:\Drivers
-For the 64-bit drivers:
- VBoxWindowsAdditions-amd64 /extract /D=C:\Drivers
Goto device manager
add hardware
Restart and connect with VNC viewer, now you should be able to change screen resolution
other valuable info on launchpad.