How to run a GUI application inside a docker container, and to access the application within a browser.
The easiest combo is to run
- Xvfb a virtual X server that can run on machines with no display hardware and no physical input devices. It emulates a dumb framebuffer using virtual memory
- a VNC server to be able to access from everywhere
- noVNC + websockify that allow to do VNC through a browser
- pulseaudio to share audio device
- a Window manager (see just below)
into an Ubuntu base image.
It is possible to choose any windows manager, but some are lighter than others. Below, there will be two simple examples with light ones:
The final image size is 1.7Go.
When building the image it is possible to specify a personal timezone
docker build . \
--file Dockerfile \
--tag docker-vnc-xfce4 \
--build-arg TZ=Europe/Paris
It takes few minutes to make it.
The built image expose standard ports:
- 22 for ssh connections
- 5900 for VNC access (here are VNC clients)
- 6080 for noVNC website
So that for browser access the full address is http://localhost:6080/vnc.html.
Applications starts with a simple user context: user (with password user01), and this user has sudo priviledges. User, password and uid/gid can be customized at startup with variables (see configuration below).
The most simple startup command is
docker run --rm \
--interactive \
--tty \
--publish 6080:6080 \
--publish ${VNC_PORT:-5900}:5900 \
--publish ${SSH_PORT:-22}:22 \
--name desktop \
--env LANG=fr_FR.UTF-8 \
--env USR_UID=$(id -u) \
--env USR_GID=$(id -g) \
docker-vnc-xfce4
Some variables can be passed to the docker run command to modify image behavior.
| Name | Description |
|---|---|
| DESKTOP_ADDITIONAL_PROGRAMS | Automatically starts a program (ratpoison only) |
| DESKTOP_BACKGROUND_IMAGE | Default background image (can be an url) |
| DESKTOP_ENV | Choose desktop environment (between ratpoison and xfce4) |
| DESKTOP_KEYBOARD_LAYOUT | Specify default keyboard layout (format: layout/variant) |
| DESKTOP_SIZE | Define the screen size (default 1280x1024) |
| DESKTOP_THEME | Set the default Xfce4 theme |
| DESKTOP_VNC_PASSWORD | Set a VNC password (default is none) |
| USR | The username that runs the VNC server (default is user) |
| USR_GID | The gid (group id) of the user USR (default is 6000) |
| USR_PASS | The password of the default user (default is user01) |
| USR_UID | The uid (user id) of the user USR (default is 6000) |
Example: run Xfce4 in french, with desktop personal settings and sound
docker run --rm \
--interactive \
--tty \
--volume /run/user/$(id -u)/pulse/native:/run/user/1000/pulse/native \
--privileged \
--publish 6080:6080 \
--publish ${VNC_PORT:-5900}:5900 \
--publish ${SSH_PORT:-22}:22 \
--name desktop \
--env DESKTOP_ENV=xfce4 \
--env LANG=fr_FR.UTF-8 \
--env DESKTOP_KEYBOARD_LAYOUT="fr/azerty" \
--env DESKTOP_SIZE="1920x1080" \
--env DESKTOP_THEME="Greybird-dark" \
--env DESKTOP_BACKGROUND_IMAGE="https://upload.wikimedia.org/wikipedia/commons/9/96/Alberi_AlpediSiusi.JPG" \
--env USR_UID=$(id -u) \
--env USR_GID=$(id -g) \
docker-vnc-xfce4 /bin/bash
In the ratpoison example a firefox browser is started in the image.
To use another application it is necessary to
- first install it, either
- in Dockerfile at line 96:
RUN apt-get install ... notepadqq(here we addnotepadqq) - by setting variable
INSTALL_ADDITIONAL_PROGRAMSat run
- in Dockerfile at line 96:
- then run it, by setting it in variable
DESKTOP_ADDITIONAL_PROGRAMS
Example: run ratpoison with spider cards games in an interactive container
docker run --rm \
--interactive \
--tty \
--privileged \
--publish 6080:6080 \
--publish ${VNC_PORT:-5900}:5900 \
--publish ${SSH_PORT:-22}:22 \
--name desktop \
--env LANG=fr_FR.UTF-8 \
--env DESKTOP_ENV=ratpoison \
--env DESKTOP_SIZE="1024x800" \
--env INSTALL_ADDITIONAL_PROGRAMS=aisleriot \
--env DESKTOP_ADDITIONAL_PROGRAMS="/bin/sh -c '/usr/games/sol -v spider'" \
--env USR_UID=$(id -u) \
--env USR_GID=$(id -g) \
docker-vnc-xfce4 /bin/bash
For more informations on ratpoison desktop manager see general use page.
This image is designed to accept private CA certificates. Just mount them in /usr/local/share/ca-certificates directory, and they will be loaded at startup.
It is possible to customize image statup by mounting scripts into the container:
/prestartup.sh: if present this script is executed at very begining of theentrypointscript before anything else (even before user creation)/poststartup.sh: if present this script is executed at the end of theentrypointscript just before waiting for connections/startup.sh: if present this script is executed at the end of theentrypointscript to wait for connections
