Running Xvfb with firefox

Question

I´m trying to run headlesless firefox with this command sudo xvfb-run -a firefox http://google.com so i get this error

(process:9000): GLib-CRITICAL **: g_slice_set_config: assertion 'sys_page_size == 0' failed
Xlib:  extension "RANDR" missing on display ":113".

I have searched to solve this problem referring to this link https://stackoverflow.com/questions/17944234/xlib-extension-randr-missing-on-display-21-trying-to-run-headless-googl

Xvfb :113 -screen 0 1024x768x24 -extension RANDR &

when I rerun the same commande i got Xlib: extension "RANDR" missing on display ":114". and so on

How could I solve this problem? Any solution will be grateful

Solution

Run xvfb-run as:

xvfb-run -a -s "-screen 0 1024x768x24" firefox http://google.com

Running Xvfb, and then xvfb-run will not cause the latter incarnation to run on the display of the former Xvfb. You'd need to set the DISPLAY variable for the app you wish to run on that other display, if you wish to run Xvfb by hand.

You do not need the RANDR extension for Firefox anyway. It doesn't need to resize the display while running.

Comments

[Bessa]

what do you by I " need to set the DISPLAY variable for the app I wish to run on that other display, if I wish to run Xvfb by hand."

[Bessa]

I was running this command on my terminal xvfb-run -a -s "-screen 0 1024x768x24" firefox http://google.com but i have another error Xlib: extension "RANDR" missing on display ":99". console.error: Could not read session file Message: Unix error 13 during operation open on file /.mozilla/firefox/zcu.default/sessionstore-backups/recovery.‌​js (Permission denied)

[Bessa]

when I run this command $ls -al /.mozilla/firefox/zcu.default/sessionstore-backups/recovery.‌​js this is the output -rw-------