docker-alpine-desktop

A desktop envirunment based on alpine and xfce4 wich runs in a docker container with a WEB VNC

You can invite me to a beer if you want ;)

This is a completely funcional Docker image with a xfce4 desktop environment.

Based on Alpine Linux, which provides a very small size.

Tested and working on x86_64 devices.

Thanks to @jlesage for a great base image for GUI apps.

Instructions:

• Map any local port to 5800 for web access
• Map any local port to 5900 for VNC access
• Map a local volume to /config (Stores configuration data)
• Map a local volume to /shared (Access media files)

Sample run command:

docker run -d --name=alpine-desktop \
-v /share/Container/alpine-desktop/config:/config \
-v /share/Container/alpine-desktop/media:/media \
-e GROUP_ID=1000 \
-e USER_ID=1000 \
-e TZ=Europe/Berlin \
-e RCLONE_CONFIG_REMOTE=plexdrive_crypt \
--cap-add SYS_ADMIN \
--device /dev/fuse \
--shm-size 2g \
-p 5800:5800 \
-p 5900:5900 \
shokinn/alpine-desktop:latest

docker run --rm -p 5800:5800 -p 5900:5900 -v /Users/phg/Downloads/config:/config -e RCLONE_CONFIG_REMOTE=plexdrive_crypt --cap-add SYS_ADMIN --device /dev/fuse docker-alpine-desktop:latest

Browse to http://your-host-ip:5800 to access the alpine-desktop GUI.

Environment Variables

To customize some properties of the container, the following environment variables can be passed via the -e parameter (one for each variable). Value of this parameter has the format <VARIABLE_NAME>=<VALUE>.

Variable	Description	Default
USER_ID	ID of the user the application runs as. See User/Group IDs to better understand when this should be set.	1000
GROUP_ID	ID of the group the application runs as. See User/Group IDs to better understand when this should be set.	1000
SUP_GROUP_IDS	Comma-separated list of supplementary group IDs of the application.	(unset)
UMASK	Mask that controls how file permissions are set for newly created files. The value of the mask is in octal notation. By default, this variable is not set and the default umask of 022 is used, meaning that newly created files are readable by everyone, but only writable by the owner. See the following online umask calculator: http://wintelguy.com/umask-calc.pl	(unset)
TZ	TimeZone of the container. Timezone can also be set by mapping /etc/localtime between the host and the container.	Etc/UTC
KEEP_APP_RUNNING	When set to 1, the application will be automatically restarted if it crashes or if user quits it.	0
APP_NICENESS	Priority at which the application should run. A niceness value of -20 is the highest priority and 19 is the lowest priority. By default, niceness is not set, meaning that the default niceness of 0 is used. NOTE: A negative niceness (priority increase) requires additional permissions. In this case, the container should be run with the docker option --cap-add=SYS_NICE.	(unset)
CLEAN_TMP_DIR	When set to 1, all files in the /tmp directory are delete during the container startup.	1
DISPLAY_WIDTH	Width (in pixels) of the application's window.	1280
DISPLAY_HEIGHT	Height (in pixels) of the application's window.	768
SECURE_CONNECTION	When set to 1, an encrypted connection is used to access the application's GUI (either via web browser or VNC client). See the Security section for more details.	0
VNC_PASSWORD	Password needed to connect to the application's GUI. See the VNC Password section for more details.	(unset)
X11VNC_EXTRA_OPTS	Extra options to pass to the x11vnc server running in the Docker container. WARNING: For advanced users. Do not use unless you know what you are doing.	(unset)
ENABLE_CJK_FONT	When set to 1, open source computer font WenQuanYi Zen Hei is installed. This font contains a large range of Chinese/Japanese/Korean characters.	0
RCLONE_CONFIG_FILE_NAME	File name of the rclone config which have to be placed in /config/rclone/.	rclone.conf
RCLONE_CONFIG_REMOTE	Remote name in the rclong config file which should be mounted.	gdrive
RCLONE_CONFIG_REMOTE_PATH	[Optional] Path in the remote which should be mounted as base path.	""

Data Volumes

The following table describes data volumes used by the container. The mappings are set via the -v parameter. Each mapping is specified with the following format: <HOST_DIR>:<CONTAINER_DIR>[:PERMISSIONS].

Container path	Permissions	Description
/config	rw	This is where the application stores its configuration, log and any files needing persistency.
/storage	rw	This is where downloaded files are stored, or where you put files in your host for uploading.

Ports

Here is the list of ports used by the container. They can be mapped to the host via the -p parameter (one per port mapping). Each mapping is defined in the following format: <HOST_PORT>:<CONTAINER_PORT>. The port number inside the container cannot be changed, but you are free to use any port on the host side.

Port	Mapping to host	Description
5800	Mandatory	Port used to access the application's GUI via the web interface.
5900	Optional	Port used to access the application's GUI via the VNC protocol. Optional if no VNC client is used.

User/Group IDs

When using data volumes (-v flags), permissions issues can occur between the host and the container. For example, the user within the container may not exists on the host. This could prevent the host from properly accessing files and folders on the shared volume.

To avoid any problem, you can specify the user the application should run as.

This is done by passing the user ID and group ID to the container via the USER_ID and GROUP_ID environment variables.

To find the right IDs to use, issue the following command on the host, with the user owning the data volume on the host:

id <username>

Which gives an output like this one:

uid=1000(myuser) gid=1000(myuser) groups=1000(myuser),4(adm),24(cdrom),27(sudo),46(plugdev),113(lpadmin)

The value of uid (user ID) and gid (group ID) are the ones that you should be given the container.

Security

By default, access to the application's GUI is done over an unencrypted connection (HTTP or VNC).

Secure connection can be enabled via the SECURE_CONNECTION environment variable. See the Environment Variables section for more details on how to set an environment variable.

When enabled, application's GUI is performed over an HTTPs connection when accessed with a browser. All HTTP accesses are automatically redirected to HTTPs.

When using a VNC client, the VNC connection is performed over SSL. Note that few VNC clients support this method. SSVNC is one of them.

Certificates

Here are the certificate files needed by the container. By default, when they are missing, self-signed certificates are generated and used. All files have PEM encoded, x509 certificates.

Container Path	Purpose	Content
/config/certs/vnc-server.pem	VNC connection encryption.	VNC server's private key and certificate, bundled with any root and intermediate certificates.
/config/certs/web-privkey.pem	HTTPs connection encryption.	Web server's private key.
/config/certs/web-fullchain.pem	HTTPs connection encryption.	Web server's certificate, bundled with any root and intermediate certificates.

NOTE: To prevent any certificate validity warnings/errors from the browser or VNC client, make sure to supply your own valid certificates.

NOTE: Certificate files are monitored and relevant daemons are automatically restarted when changes are detected.

VNC Password

To restrict access to your application, a password can be specified. This can be done via two methods:

• By using the VNC_PASSWORD environment variable.
• By creating a .vncpass_clear file at the root of the /config volume. This file should contains the password in clear-text. During the container startup, content of the file is obfuscated and moved to .vncpass.

The level of security provided by the VNC password depends on two things:

• The type of communication channel (encrypted/unencrypted).
• How secure access to the host is.

When using a VNC password, it is highly desirable to enable the secure connection to prevent sending the password in clear over an unencrypted channel.

ATTENTION: Password is limited to 8 characters. This limitation comes from the Remote Framebuffer Protocol RFC (see section 7.2.2). Any characters beyhond the limit are ignored.

Shell Access

To get shell access to a the running container, execute the following command:

docker exec -ti CONTAINER sh

Where CONTAINER is the ID or the name of the container used during its creation (e.g. alpine-desktop).

Reverse Proxy

The following sections contains NGINX configuration that need to be added in order to reverse proxy to this container.

A reverse proxy server can route HTTP requests based on the hostname or the URL path.

Routing Based on Hostname

In this scenario, each hostname is routed to a different application/container.

For example, let's say the reverse proxy server is running on the same machine as this container. The server would proxy all HTTP requests sent to alpine-desktop.domain.tld to the container at 127.0.0.1:5800.

Here are the relevant configuration elements that would be added to the NGINX configuration:

map $http_upgrade $connection_upgrade {
	default upgrade;
	''      close;
}

upstream alpine-desktop {
	# If the reverse proxy server is not running on the same machine as the
	# Docker container, use the IP of the Docker host here.
	# Make sure to adjust the port according to how port 5800 of the
	# container has been mapped on the host.
	server 127.0.0.1:5800;
}

server {
	[...]

	server_name alpine-desktop.domain.tld;

	location / {
	        proxy_pass http://alpine-desktop;
	}

	location /websockify {
		proxy_pass http://alpine-desktop;
		proxy_http_version 1.1;
		proxy_set_header Upgrade $http_upgrade;
		proxy_set_header Connection $connection_upgrade;
		proxy_read_timeout 86400;
	}
}

Routing Based on URL Path

In this scenario, the hostname is the same, but different URL paths are used to route to different applications/containers.

For example, let's say the reverse proxy server is running on the same machine as this container. The server would proxy all HTTP requests for server.domain.tld/alpine-desktop to the container at 127.0.0.1:5800.

Here are the relevant configuration elements that would be added to the NGINX configuration:

map $http_upgrade $connection_upgrade {
	default upgrade;
	''      close;
}

upstream alpine-desktop {
	# If the reverse proxy server is not running on the same machine as the
	# Docker container, use the IP of the Docker host here.
	# Make sure to adjust the port according to how port 5800 of the
	# container has been mapped on the host.
	server 127.0.0.1:5800;
}

server {
	[...]

	location = /alpine-desktop {return 301 $scheme://$http_host/alpine-desktop/;}
	location /alpine-desktop/ {
		proxy_pass http://alpine-desktop/;
		location /alpine-desktop/websockify {
			proxy_pass http://alpine-desktop/websockify/;
			proxy_http_version 1.1;
			proxy_set_header Upgrade $http_upgrade;
			proxy_set_header Connection $connection_upgrade;
			proxy_read_timeout 86400;
		}
	}
}

Support or Contact

Having troubles with the container or have questions? Please [create a new issue].