Remote desktop is extremely useful when you want to have a continuous work experience, that is, work everywhere with the same environment. This post shares my own experience on remote desktop among various usage cases.
Case 1: Desktop on Shared Server
I started working on a desktop server in the lab since 2016. During that time, the server was of the highest performance among the machines in the lab so everyone wanted to use it. The server was a Linux machine so SSH would be fine, however I found it insufficient when I wanted to handle some large projects in an IDE or a GUI text editor.
I chose to use a normal VNC server (
vnc4server in this case) to solve the problem.
vnc4server would open a new X server and log you into a new desktop (not the same with what is shown on the real monitor). This suffices because at that time I didn’t need access to the server through the real monitor.
vnc4server case, one can start a normal VNC server by
$ vnc4server -depth 24 -geometry 1920x1080
-depth option controls the pixel depth and the
-geometry controls the resolution. You can see the output like
New 'debian-yzy:2 (yzy)' desktop is debian-yzy:2 Starting applications specified in /home/yzy/.vnc/xstartup Log file is /home/yzy/.vnc/debian-yzy:2.log
The number 2 in
debian-yzy:2 is the X display number assigned to the new desktop. Now you can connect to this desktop using any typical VNC client, using
<host>:<5900+display_number> as the target.
If you want to kill the desktop, you have to specify the X display number, like
$ vnc4server -kill :2
xstartup file needs more configuration if you meet white screen or blank screen cases, which we won’t mention here. Just Google it for more information.
Case 2: Desktop on Personal PC
Several months later I got my own PC in the lab. This PC’s performance was a little bit weaker than the lab server, however already enough for most of my work. So I moved all my code and data into my own PC, and did most of my work through its real monitor. The problem was that, if I wanted to work remotely on this machine, it was important to reuse the default desktop since the all my work context was there. The case 1 solution no longer works because
vnc4server can only start new X servers.
A common solution here is to use
x11vnc currently doesn’t support Wayland. Please use Xorg here. This software connects to an opened X display and forwards its content to a VNC client. Assume you’ve logged into a desktop (which is a must in this case) and the display number is :0 (typically), you can start the x11vnc by
$ x11vnc -display :0
and the output might be like
... The VNC desktop is: debian-yzy:0 PORT=5900
x11vnc will be listening to a VNC connection at port 5900. You can then connect to it, and enjoy the same output with the real monitor.
Case 3: What if Personal PC Crashed
Since case 2 I’ve experienced several crashes of my PC, including X server crash, kernel panic (too bad), etc. After these crashes, there would be no opened X display since there is no user logged into X desktop yet, so we cannot start a shadow display using commands in case 2.
To solve the problem, one have to get access to the login greeter.
x11vnc actually does have this functionality, but it’s not well documented. I’ll try to give a reasonable explanation here, in Gnome 3 case.
First, to access the login greeter, use
$ sudo x11vnc -display :0 -auth /run/user/<gdm-uid>/gdm/Xauthority
assuming that the greeter is opened on display :0. the
gdm-uid is the uid of user in which most of Gnome’s operations are done, in my case it’s 118. The
-auth option specifies the authority cookie of opened X (see
x11vnc’s official FAQ). After that connect to this x11vnc service and you should be able to login. However, after login, you might meet a black screen. This is because a new X display is opened. You can use
$ ps aux | grep Xorg
to have a look. In my case, the output is like
Debian-+ 1309 0.0 0.3 313660 74920 tty1 Sl+ 10:42 0:01 /usr/lib/xorg/Xorg vt1 -displayfd 3 -auth /run/user/118/gdm/Xauthority -background none -noreset -keeptty -verbose 3 yzy 1763 4.0 0.6 434776 127408 tty2 Rl+ 10:43 8:24 /usr/lib/xorg/Xorg vt2 -displayfd 3 -auth /run/user/1000/gdm/Xauthority -background none -noreset -keeptty -verbose 3
You can see that a new authority cookie for uid 1000 is generated. Now you can access your own desktop using
$ x11vnc -display :1 -auth /run/user/<user-uid>/gdm/Xauthority
in my case
<user-uid> is 1000. Note that the display number is :1, since the old display is still opened, though black screen.
Remote desktop provides most complete and continuous experience for remote working, because you can reuse all the programs (like Android Studio) installed on, all code (like AOSP) and data (like Android Virtual Machine) stored in, and all the devices (like Android phones) connected to the remote PC.
Only Android guys as lazy as you need your solution
I’m now seeking a solution for case 4: what if a personal PC suffers a power supply interruption…maybe waking up it by Ethernet is a solution.
So why not use cloud computing service