The documentation says:
Xvfb screen changes the screen resolution and pixel depth, it needs to be in WxHxD format (i.e. 1600x1200x24). The default is 1024x768x24.
I just installed the xvfb-plugin, and took all the defaults, leaving the "screen" value blank. When running my Jenkins job, the first time, in the log I could see:
and at the end of the job:
Running the exact same job every subsequent time, the log say:
Looking at running jobs (using `ps -ef | grep -i xvfb`), I got nothing.
Trying this same command from the command line interface, I get:
Finally I decided to specify something for the "screen" parameter - I used the supposed default: "1024x768x24" - and everything worked fine.