x11docker allows to run graphical desktop applications (and entire desktops) in Docker Linux containers.
- Docker allows to run applications in an isolated container environment. Containers need much less resources than virtual machines for similar tasks.
- Docker does not provide a display server that would allow to run applications with a graphical user interface.
- x11docker fills the gap. It runs an X display server on the host system and provides it to Docker containers.
- Additionally x11docker does some security setup to enhance container isolation and to avoid X security leaks. This allows a sandbox environment that fairly well protects the host system from possibly malicious or buggy software.
Software can be installed in a deployable Docker image with a rudimentary Linux system inside. This can help to run or deploy software that is difficult to install on several systems due to dependency issues. It is possible to run outdated versions or latest development versions side by side. Files to work on can be shared between host and container.
x11docker runs on Linux and (with some setup and limitations) on MS Windows. x11docker is not adapted to run on macOS except in a Linux VM.
x11docker wiki provides some how-to's for basic setups without x11docker.
- Focus on security:
- Avoids X security leaks by running additional X servers.
- Restricts container capabilities to bare minimum.
- Container user is same as host user to avoid root in container.
- Low dependencies:
- No obliging dependencies on host beside X and Docker. Recommended:
xpra
andXephyr
. - No dependencies inside of Docker images except for some optional features.
- No obliging dependencies on host beside X and Docker. Recommended:
- Several optional features like GPU, sound, webcam and printer support.
- Remote access with SSH, VNC or HTML5 possible.
- Easy to use. Examples:
x11docker jess/cathode
x11docker --desktop --size 320x240 x11docker/lxde
(needs nested X serverXephyr
)
- GUI for x11docker
- Terminal usage
- Options
- Security
- Installation
- Dependencies
- Troubleshooting
- Contact
- Examples
x11docker-gui
is an optional graphical frontend for x11docker
. It runs from console, too.
x11docker-gui
needs packagekaptain
. If your distribution misses it, look at kaptain repository.- If
kaptain
is not installed on your system,x11docker-gui
uses imagex11docker/kaptain
.
Just type x11docker IMAGENAME [COMMAND]
.
- Get an overview of options with
x11docker --help
.- For desktop environments in image add option
-d, --desktop
. - To run without X at all use option
-t, --tty
. - Get an interactive TTY with option
-i, --interactive
. - See generated
docker
command (and further infos) with option--debug
.
- For desktop environments in image add option
- If startup fails, look at chapter Troubleshooting.
General syntax:
To run a Docker image with new X server:
x11docker [OPTIONS] IMAGE [COMMAND]
x11docker [OPTIONS] -- IMAGE [COMMAND [ARG1 ARG2 ...]]
x11docker [OPTIONS] -- DOCKER_RUN_OPTIONS -- IMAGE [COMMAND [ARG1 ARG2 ...]]
To run a host application on a new X server:
x11docker [OPTIONS] --exe COMMAND
x11docker [OPTIONS] --exe -- COMMAND [ARG1 ARG2 ...]
To run only a new empty X server:
x11docker [OPTIONS] --xonly
DOCKER_RUN_OPTIONS
are just added to docker run
command without a check by x11docker.
Description of some commonly used feature options.
- Some of these options have dependencies on host and/or in image. Compare wiki: feature dependencies.
If no X server option is specified, x11docker automatically chooses one depending on installed dependencies and on given or missing options --desktop
, --gpu
and --wayland
. Most recommended are xpra
and Xephyr
.
- Overview of all possible X server and Wayland options.
- Hints to use option
--xorg
within X. - Use option
-t, --tty
to run without X at all.
- Hints to use option
x11docker assumes that you want to run a single application in seamless mode, i.e. a single window on your regular desktop. If you want to run a desktop environment in image, add option --desktop
.
- Seamless mode is supported with options
--xpra
and--nxagent
. As a fallback insecure option--hostdisplay
is possible.- If neither
xpra
nornxagent
are installed, but x11docker finds a desktop capable X server likeXephyr
, it avoids insecure option--hostdisplay
and runs Xephyr with a host window manager.- You can specify a host window manager with option
--wm=WINDOWMANAGER
, for example--wm=openbox
.
- You can specify a host window manager with option
- If neither
- Desktop mode with
--desktop
is supported with all X server options except--hostdisplay
. If available, x11docker prefers--xephyr
and--nxagent
.
Changes in a running Docker container system will be lost, the created Docker container will be discarded. For persistent data storage you can share host directories:
- Option
-m, --home
creates a host directory in~/.local/share/x11docker/IMAGENAME
that is shared with the container and mounted as itsHOME
directory. Files in container home and configuration changes will persist. x11docker creates a softlink from~/.local/share/x11docker
to~/x11docker
. - Option
--sharedir DIR
mounts a host directory at the same location in container.--sharedir DIR:ro
restricts to read-only access. - Option
--homedir DIR
is similar to--home
but allows you to specify a custom host directory for data storage. - Special cases for
$HOME
:--homedir $HOME
will use your host home as container home. Discouraged, use with care.--sharedir $HOME
will symlink your host home as a subfolder of container home.
Note that x11docker copies files from /etc/skel
in container to HOME
if HOME
is empty. That allows to provide customized user settings.
Hardware acceleration for OpenGL is possible with option -g, --gpu
.
- This will work out of the box in most cases with open source drivers on host. Otherwise have a look at wiki: feature dependencies.
- Closed source NVIDIA drivers need some setup and support less x11docker X server options.
Clipboard sharing is possible with option -c, --clipboard
.
- Image clips are possible with
--xpra
and--hostdisplay
. - Some X server options need package
xclip
on host.
Sound is possible with options -p, --pulseaudio
and --alsa
.
- For pulseaudio sound with
--pulseaudio
you needpulseaudio
on host andpulseaudio
libraries in image. Compare wiki: feature dependencies. - For ALSA sound with
--alsa
you might need to specify a sound card with e.g.--alsa=Generic
. Get a list of available sound cards withaplay -l
.
Webcams on host can be shared with option --webcam
.
- If webcam application in image fails, install
--gpu
dependencies in image. Compare wiki: feature dependencies. guvcview
needs--pulseaudio
or--alsa
.cheese
andgnome-ring
need--init=systemd
or--dbus-system
.
Printers on host can be provided to container with option --printer
.
- It needs
cups
on host, the default printer server for most linux distributions. - The container needs
cups
client libraries in image. Compare wiki: feature dependencies.
x11docker provides option --lang
for flexible language locale settings.
--lang
without an argument setsLANG
in container to same as on host. Same as--lang=$LANG
- x11docker will check on container startup if the desired locale is already present in image and enable it.
- If x11docker does not find the locale, it creates it on container startup. This needs some
locale
packages in image. Compare wiki: feature dependencies. - Examples:
--lang=de
for German,--lang=zh_CN
for Chinese,--lang=ru
for Russian,--lang=$LANG
for your host locale. - For support of chinese, japanese and korean characters install a font like
fonts-arphic-uming
in image.
To run Wayland instead of an X server x11docker provides options --wayland
, --weston
, --kwin
and --hostwayland
.
For further description loot at wiki: Description of Wayland options.
- Option
--wayland
automatically sets up a Wayland environment with some related environment variables. - Options
--kwin
and--weston
run Wayland compositorskwin_wayland
orweston
.- For QT5 applications without option
--wayland
add options--dbus
and--env QT_QPA_PLATFORM=wayland
.
- For QT5 applications without option
- Option
--hostwayland
can run single applications on host Wayland desktops like Gnome 3, KDE 5 and Sway. - Example:
xfce4-terminal
on Wayland:x11docker --wayland x11docker/xfce xfce4-terminal
x11docker supports several init systems as PID 1 in container with option --init
. Init in container solves the zombie reaping issue.
As default x11docker uses tini
in/usr/bin/docker-init
. Also available are systemd
, SysVinit
, runit
, OpenRC
and s6-overlay
. elogind
is supported, too.
Look at wiki: Init systems in Docker.
Some desktop environments and applications need a running DBus daemon and/or DBus user session. DBus options need dbus
in image.
- use
--dbus
to run a DBus user session daemon. - use
--dbus-system
to run DBus system daemon. This includes option--dbus
.- If startup fails or takes about 90s, install an init system and use that one to run DBus. E.g. install
systemd
in image and run with--init=systemd
.
- If startup fails or takes about 90s, install an init system and use that one to run DBus. E.g. install
- use
--hostdbus
to connect to host DBus user session. - use
--sharedir /run/dbus/system_bus_socket
to share host DBus system socket. - DBus will be started automatically with init systems
systemd
,openrc
,runit
andsysvinit
(option--init
).
Scope of x11docker is to run containerized GUI applications while preserving and improving container isolation. Core concept is:
- Runs a second X server to avoid X security leaks.
- This in opposite to widespread solutions that share host X socket of display :0, thus breaking container isolation, allowing keylogging and remote host control.
(However, x11docker provides this with fallback option
--hostdisplay
). - Authentication is done with MIT-MAGIC-COOKIE, stored separate from file
~/.Xauthority
.
- This in opposite to widespread solutions that share host X socket of display :0, thus breaking container isolation, allowing keylogging and remote host control.
(However, x11docker provides this with fallback option
- Creates container user similar to host user to avoid root in container.
- You can also specify another user with
--user=USERNAME
or a non-existing one with--user=UID:GID
. - Disables possible root password and deletes entries in
/etc/sudoers
.- If you want root permissions in container, use option
--sudouser
that allowssu
andsudo
with passwordx11docker
. Alternatively you can run with--user=root
.
- If you want root permissions in container, use option
- If you want to use
USER
specified in image instead, set option--user=RETAIN
. x11docker won't change container's/etc/passwd
or/etc/sudoers
in that case. Option--home
won't be available.
- You can also specify another user with
- Reduces container capabilities to bare minimum.
- Sets docker run option
--cap-drop=ALL
to drop all capabilities. Most applications don't need them. - Sets docker run option
--security-opt=no-new-privileges
. - These restrictions can be disabled with x11docker option
--cap-default
or reduced with--sudouser
or--user=root
.
- Sets docker run option
That being said, Docker's default capabilities and its seccomp profile are not bad. I am not aware of an escape from a container without an additional isolation degrading option or configuration. However, x11docker follows the principle of least privilege. Docker containers should not have capabilities or privileges that they don't need for their job.
Weaknesses:
- Possible SELinux restrictions are degraded for x11docker containers with docker run option
--security-opt label=type:container_runtime_t
to allow access to new X unix socket. A more restrictive solution is desirable. Compare: SELinux and Docker: allow access to X unix socket in /tmp/.X11-unix - User namespace remapping is disabled to allow options
--home
and--homedir
without file ownership issues. (Though, this is less an issue because x11docker already avoids root in container). Exception: User namespace remapping is not disabled for--user=RETAIN
. - x11docker provides several different X server options. Each X server involved might have its individual vulnerabilities. x11docker only covers well-known X security leaks that result from X11 protocol design.
x11docker shows warning messages in terminal if chosen options degrade container isolation. Note that x11docker does not check custom DOCKER_RUN_OPTIONS
.
Most important:
--hostdisplay
shares host X socket of display :0 instead of running a second X server.- Danger of abuse is reduced providing so-called untrusted cookies, but do not rely on this.
- If additionally using
--gpu
or--clipboard
, option--hostipc
and trusted cookies are enabled and no protection against X security leaks is left. - If you don't care about container isolation,
x11docker --hostdisplay --gpu
is an insecure but quite fast setup without any overhead.
--gpu
allows access to GPU hardware. This can be abused to get window content from host (palinopsia bug) and makes GPU rootkits possible.--pulseaudio
and--alsa
allow catching audio output and microphone input from host.
Rather special options reducing security, but not needed for regular use:
--sudouser
and--user=root
allowsu
andsudo
with passwordx11docker
for container user. If an application somehow breaks out of container, it can harm your host system. Allows many container capabilties that x11docker would drop otherwise.--cap-default
disables x11docker's container security hardening and falls back to default Docker container capabilities. If an application somehow breaks out of container, it can harm your host system.--dbus-system
and--init=systemd|sysvinit|openrc|runit
allow some container capabilities that x11docker would drop otherwise.--init=systemd
also shares access to/sys/fs/cgroup
. Some processes will run as root in container. If a root process somehow breaks out of container, it can harm your host system. Allows many container capabilties that x11docker would drop otherwise.--hostipc
sets docker run option--ipc=host
. Allows MIT-SHM / shared memory. Disables IPC namespacing.--hostnet
sets docker run option--net=host
. Shares host network stack. Disables network namespacing. Container can spy on an maybe manipulate host network traffic.--hostdbus
allows communication over DBus with host applications.
Container isolation enhanced with x11docker allows to use containers as a sandbox that fairly well protects the host system from possibly malicious or buggy software. Though, no sandbox solution in the wild can provide a perfect secure protection, and Docker even with enhanced security settings from x11docker is no exception.
Using Docker with x11docker as a sandbox is not intended to run obviously evil software. Rather use it as:
- Compatibility environment to run software that is hard or impossible to install on host due to dependency issues.
- Development environment to collect libraries, compiler and so on to keep the host clean.
- Development environment to mitigate damage caused by unexpected/buggy behaviour.
- Security layer for software that may be malicious in worst case. Examples: Internet browser with Javascript enabled, or wine with Windows applications.
x11docker already restricts process capabilities. You can additionally restrict access to CPU and RAM with option --limit
.
As default --limit
restricts to 50% of available CPUs and 50% of currently free RAM. Another amount can be specified with --limit=FACTOR
with a FACTOR
greater than zero and less than or equal 1.
For more custom fine tuning have a look at Docker documentation: Limit a container's resources.
NOTE: Internet access is allowed per default. You can disable internet access with --no-internet
.
WARNING: There is no restriction that can prevent the container from flooding the hard disk in Docker's container partition or in shared folders.
To check container isolation and some feature options use image x11docker/check
and try out with several options.
- An insecure setup is
x11docker --hostdisplay --gpu x11docker/check
. It fairly well demonstrates common X security leaks. - Add options like
--pulseaudio --alsa --webcam --clipboard
to check their functionality.
Note that x11docker is just a bash script without library dependencies. Basically it is a wrapper for X servers and Docker. To allow advanced usage of x11docker abilities look at chapter Dependencies.
As root you can install, update and remove x11docker to system directories to be available system-wide:
x11docker --install
: install x11docker and x11docker-gui from current directory. (Useful to install from an extractedzip
file or a clonedgit
repository.)x11docker --update
: download and install latest release from github.x11docker --update-master
: download and install latest master version from github.x11docker --remove
: remove all files installed by x11docker.
Copies x11docker
and x11docker-gui
to /usr/bin
. Creates an icon in /usr/share/icons
.
Creates x11docker.desktop
in /usr/share/applications
. Copies README.md
, CHANGELOG.md
and LICENSE.txt
to /usr/share/doc/x11docker
.
- For systems using
sudo
:curl -fsSL https://raw.githubusercontent.com/mviereck/x11docker/master/x11docker | sudo bash -s -- --update
- Directly as
root
:curl -fsSL https://raw.githubusercontent.com/mviereck/x11docker/master/x11docker | bash -s -- --update
You can run x11docker from an arbitray location with bash x11docker
.
For minimal system-wide installation make x11docker
executable with chmod +x x11docker
and move it to /usr/bin
(or another location in PATH
).
Other files than x11docker
script itself are not essential.
x11docker can run natively on MS Windows electively in one of:
It needs X server VcXsrv.exe
or Xwin.exe
. Further informations at wiki: x11docker on MS Windows.
x11docker can run with standard system utilities without additional dependencies on host or in image.
- As a core it only needs
bash
, anX
server anddocker
to run Docker containers on X. - x11docker checks dependencies for chosen options on startup and shows terminal messages if some are missing.
For advanced usage of x11docker it is recommended to install some additional packages.
The recommended base commands are: xpra
Xephyr
weston
Xwayland
xdotool
xauth
xinit
xclip
xhost
xrandr
xdpyinfo
. Some of them are probably already installed.
- To provide these base commands see wiki: Dependencies - Recommended base for a package list matching your distribution.
Some feature options have additional dependencies on host and/or in image. This affects especially options --gpu
, --printer
and --pulseaudio
.
Compare wiki: feature dependencies.
For troubleshooting, run x11docker
or x11docker-gui
in a terminal.
- x11docker shows warnings if something is insecure, missing or going wrong.
- Use option
-v, --verbose
to see full logfile output.- Option
-D, --debug
gives a less verbose output. - You can find the latest dispatched logfile at
~/.cache/x11docker/x11docker.log
.
- Option
- Use option
- Some applications fail with fallback option
--hostdisplay
. Add--clipboard
to disable some security restrictions. If that does not help, install additional X servers. - Make sure your x11docker version is up to date with
x11docker --update
(latest release) orx11docker --update-master
(latest beta). - The image may have a
USER
specification and be designed for this user. x11docker sets up a container user that can mismatch this container user setup.- Check for a
USER
specification in image withdocker inspect --format '{{.Config.User}}' IMAGENAME
. - If yes, try with
--user=RETAIN
to run with theUSER
specified in image.
- Check for a
- Some applications need more privileges or capabilities than x11docker provides as default.
- Reduce container isolation with e.g.:
- x11docker options:
--cap-default --hostipc --hostnet --sys-admin
. (Try--cap-default
first). - docker run options:
--cap-add ALL --security-opt seccomp=unconfined --privileged
- Example:
x11docker --cap-default --hostipc --hostnet --sys-admin -- --cap-add ALL --security-opt seccomp=unconfined --privileged -- IMAGENAME
- Try with reduced container isolation. If it works, drop options one by one until the needed one(s) are left.
- If
--cap-add ALL
helps, find the capability you really need and add only that one. - If
--privileged
helps, your application probably needs a device in/dev
. Find out which one and share it with e.g.--device /dev/vboxdrv
. Try also--sharedir /dev/udev/data:ro
.- Please, don't use
--privileged
as a solution. It allows too much access to host and fatally breaks container isolation. Investigate the permissions your container needs indeed.
- Please, don't use
- x11docker options:
- You can run container applications as root with
--user=root
.
- Reduce container isolation with e.g.:
- A few applications need DBus. Install
dbus
in image and try option--dbus
. If that does not help, try option--dbus-system
. - A few applications need systemd. Install
systemd
in image and try option--init=systemd
.
Feel free to open a ticket if you have a question or encounter an issue.
If reporting an issue:
- Have a look at chapter Troubleshooting.
- Most times it makes sense to store the
--verbose
output (or~/.cache/x11docker/x11docker.log
) at pastebin.com.
If you want to contribute to x11docker, please open a ticket before creating a pull request. Often it is possible to accomplish desired tasks with already available options.
Please open a ticket if you need support. Please note that x11docker
is a non-commercial project maintained in free time.
I'll help where I can, but there is no organisation behind x11docker
that can provide large scale support.
x11docker image examples with desktop environments can be found on docker hub.
A special one to check features and container isolation is x11docker/check
.
Application | x11docker command |
---|---|
Xfce4 Terminal | x11docker x11docker/xfce xfce4-terminal |
GLXgears with hardware acceleration | x11docker --gpu x11docker/xfce glxgears |
Kodi media center with hardware acceleration, Pulseaudio sound and shared Videos folder. For setup look at ehough/docker-kodi. |
x11docker --gpu --pulseaudio --sharedir ~/Videos erichough/kodi . |
XaoS fractal generator | x11docker patricknw/xaos |
Telegram messenger with persistent HOME for configuration storage |
x11docker --home xorilog/telegram |
Firefox with shared Download folder. |
x11docker --sharedir $HOME/Downloads jess/firefox |
Tor browser | x11docker jess/tor-browser |
Chromium browser | x11docker -- jess/chromium --no-sandbox |
VLC media player with shared Videos folder and Pulseaudio sound |
x11docker --pulseaudio --sharedir=$HOME/Videos jess/vlc |
Desktop environment (most based on Debian) |
x11docker command |
---|---|
FVWM (based on Alpine, 22.5 MB) | x11docker --desktop x11docker/fvwm |
Fluxbox (based on Debian, 87 MB) | x11docker --desktop x11docker/fluxbox |
Lumina (based on Void Linux) | x11docker --desktop x11docker/lumina |
LXDE | x11docker --desktop x11docker/lxde |
LXQt | x11docker --desktop x11docker/lxqt |
Xfce | x11docker --desktop x11docker/xfce |
CDE Common Desktop Environment | x11docker --desktop --init=systemd --cap-default x11docker/cde |
Mate | x11docker --desktop x11docker/mate |
Enlightenment (based on Void Linux) | x11docker --desktop --gpu --runit x11docker/enlightenment |
Trinity (successor of KDE 3) | x11docker --desktop x11docker/trinity |
Cinnamon | x11docker --desktop --gpu --dbus-system x11docker/cinnamon |
deepin (3D desktop from China) | x11docker --desktop --gpu --init=systemd x11docker/deepin |
LiriOS (needs at least docker 18.06 or this xcb bugfix.) (based on Fedora) |
x11docker --desktop --gpu lirios/unstable |
KDE Plasma | x11docker --desktop --gpu x11docker/plasma |
KDE Plasma as nested Wayland compositor | x11docker --gpu x11docker/plasma startplasmacompositor |
LXDE with wine and PlayOnLinux and a persistent HOME folder to preserve installed Windows applications, and with Pulseaudio sound. |
x11docker --desktop --home --pulseaudio x11docker/lxde-wine |
For persistent changes of image system adjust Dockerfile and rebuild. To add custom applications to x11docker example images you can create a new Dockerfile based on them. Example:
# xfce desktop with VLC media player
FROM x11docker/xfce
RUN apt-get update && apt-get install -y vlc
Sample screenshots are stored in screenshot branch
x11docker --desktop x11docker/lxde-wine
x11docker --desktop --gpu x11docker/plasma