Remote access with SSH

SSH X forwarding

You can run x11docker on remote servers with ssh -X like a regular X application. Example:

# Replace localhost with address of your desired server

ssh -X localhost -- x11docker x11docker/lxde lxterminal

If your server has Xephyr installed, you can run desktop environments like a VNC session:

ssh -X localhost -- x11docker --desktop x11docker/lxde

SSH with xpra

SSH setup with xpra allows detaching and reattaching to a remote session.

Example for an SSH setup with xpra:

• Server setup:

# run invisible Xvfb X server with display number :30.
# catch X environment with 'read < <(...)' construct.
# docker container runs on invisible new display.
read Xenv < <(x11docker --xvfb --display=30 --showenv x11docker/lxde pcmanfm)

# Output of new X environment, just for info
echo $Xenv
# You can drop `--display=30` in command above if you provide DISPLAY
# from this output to following xpra commands instead of :30

# start xpra server with new environment variables.
# (replace "start" with "start-desktop" to forward a desktop environment)
env $Xenv xpra start :30 --use-display --start-via-proxy=no

• Client setup:

# Attach xpra client over SSH to xpra server
xpra attach ssh:$HOSTNAME:30     # replace $HOSTNAME with IP or host name of ssh server

You can detach the SSH connection and attach later again without terminating the container application:

xpra detach ssh:$HOSTNAME:30

You can stop xpra server without terminating x11docker:

xpra stop ssh:$HOSTNAME:30

SSH with xpra, second example

A script entirely executed on client. (It will ask three times for ssh password, may be solved more nicely).

#! /bin/bash

HOSTNAME=localhost                         # Change to desired server address
IMAGECOMMAND="x11docker/lxde lxterminal"   # Change to desired image name and command

# Runs x11docker on remote server. Reads new X environment variables from its output.
read Xenv < <(ssh -f $HOSTNAME -- x11docker --xvfb --showenv $IMAGECOMMAND)
# extracts display from new X environment
Newdisplay=$(sh -c "export $Xenv ; echo \$DISPLAY")
# start remote xpra server
ssh $HOSTNAME -- env $Xenv xpra start $Newdisplay --use-display --start-via-proxy=no
# start local xpra client
xpra attach ssh:$HOSTNAME$Newdisplay

SSH with xpra, annotations

• Warning: don't try this on localhost due to an xpra memory bug in xpra versions <v2.4.
• If your client does have a big display resolution or a multimonitor setup, xpra may scale up the size of forwarded windows. Check output of xrandr | grep current or xpra client output for your client display resolution. It may be e.g. 2084x768. Add --size 2048x768 to x11docker --xvfb [...] command to get a matching server display size.