• Docker container for Chromium

  

  This project implements a Docker container for Chromium, based on the docker-firefox project by jlesage.

  The GUI of the application is accessed through a modern web browser (no installation or configuration needed on the client side) or via any VNC client.

  ---

  

  Chromium is a free and open-source web browser project, principally developed and maintained by Google.

  ---

  Quick Start

  Launch the Chromium docker container with the following command:

  docker run -d \
      --name=chrome \
      -p 5800:5800 \
      -v /docker/appdata/chrome:/config:rw \
      [image_name]:[image_tag]

  Where:

  • /docker/appdata/chrome: This is where the application stores its configuration, states, log and any files needing persistency.

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

  Usage

  docker run [-d] \
      --name=chrome \
      [-e <VARIABLE_NAME>=<VALUE>]... \
      [-v <HOST_DIR>:<CONTAINER_DIR>[:PERMISSIONS]]... \
      [-p <HOST_PORT>:<CONTAINER_PORT>]... \
      ghcr.io/wowmarcomei/docker-chrome:20240911

  Parameter	Description
  -d	Run the container in the background. If not set, the container runs in the foreground.
  -e	Pass an environment variable to the container. See the Environment Variables section for more details.
  -v	Set a volume mapping (allows to share a folder/file between the host and the container). See the Data Volumes section for more details.
  -p	Set a network port mapping (exposes an internal container port to the host). See the Ports section for more details.

  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.	(no value)
  UMASK	Mask that controls how permissions are set for newly created files and folders. The value of the mask is in octal notation. By default, the default umask value is 0022, meaning that newly created files and folders are readable by everyone, but only writable by the owner. See the online umask calculator at http://wintelguy.com/umask-calc.pl.	0022
  LANG	Set the locale, which defines the application's language, if supported. Format of the locale is language[_territory][.codeset], where language is an ISO 639 language code, territory is an ISO 3166 country code and codeset is a character set, like UTF-8. For example, Australian English using the UTF-8 encoding is en_AU.UTF-8.	en_US.UTF-8
  TZ	TimeZone used by 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 when it crashes or terminates.	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. The default niceness value is 0. 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.	0
  INSTALL_PACKAGES	Space-separated list of packages to install during the startup of the container. List of available packages can be found at https://mirrors.alpinelinux.org. ATTENTION: Container functionality can be affected when installing a package that overrides existing container files (e.g. binaries).	(no value)
  PACKAGES_MIRROR	Mirror of the repository to use when installing packages. List of mirrors is available at https://mirrors.alpinelinux.org.	(no value)
  CONTAINER_DEBUG	Set to 1 to enable debug logging.	0
  DISPLAY_WIDTH	Width (in pixels) of the application's window.	1920
  DISPLAY_HEIGHT	Height (in pixels) of the application's window.	1080
  DARK_MODE	When set to 1, dark mode is enabled for the application.	0
  WEB_AUDIO	When set to 1, audio support is enabled, meaning that any audio produced by the application is played through the browser. Note that audio is not supported for VNC clients.	0
  WEB_AUTHENTICATION	When set to 1, the application' GUI is protected via a login page when accessed via a web browser. Access is allowed only when providing valid credentials. NOTE: This feature requires secure connection (SECURE_CONNECTION environment variable) to be enabled.	0
  WEB_AUTHENTICATION_USERNAME	Optional username to configure for the web authentication. This is a quick and easy way to configure credentials for a single user. To configure credentials in a more secure way, or to add more users, see the Web Authentication section.	(no value)
  WEB_AUTHENTICATION_PASSWORD	Optional password to configure for the web authentication. This is a quick and easy way to configure credentials for a single user. To configure credentials in a more secure way, or to add more users, see the Web Authentication section.	(no value)
  SECURE_CONNECTION	When set to 1, an encrypted connection is used to access the application's GUI (either via a web browser or VNC client). See the Security section for more details.	0
  SECURE_CONNECTION_VNC_METHOD	Method used to perform the secure VNC connection. Possible values are SSL or TLS. See the Security section for more details.	SSL
  SECURE_CONNECTION_CERTS_CHECK_INTERVAL	Interval, in seconds, at which the system verifies if web or VNC certificates have changed. When a change is detected, the affected services are automatically restarted. A value of 0 disables the check.	60
  WEB_LISTENING_PORT	Port used by the web server to serve the UI of the application. This port is used internally by the container and it is usually not required to be changed. By default, a container is created with the default bridge network, meaning that, to be accessible, each internal container port must be mapped to an external port (using the -p or --publish argument). However, if the container is created with another network type, changing the port used by the container might be useful to prevent conflict with other services/containers. NOTE: a value of -1 disables listening, meaning that the application's UI won't be accessible over HTTP/HTTPs.	5800
  VNC_LISTENING_PORT	Port used by the VNC server to serve the UI of the application. This port is used internally by the container and it is usually not required to be changed. By default, a container is created with the default bridge network, meaning that, to be accessible, each internal container port must be mapped to an external port (using the -p or --publish argument). However, if the container is created with another network type, changing the port used by the container might be useful to prevent conflict with other services/containers. NOTE: a value of -1 disables listening, meaning that the application's UI won't be accessible over VNC.	5900
  VNC_PASSWORD	Password needed to connect to the application's GUI. See the VNC Password section for more details.	(no value)
  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
  FF_OPEN_URL	The URL to open when Chrome starts.	(no value)
  FF_KIOSK	Set to 1 to enable kiosk mode. This mode launches Chrome in a very restricted and limited mode best suitable for public areas or customer-facing displays.	0
  FF_CUSTOM_ARGS	Custom argument(s) to pass when launching Chrome.	0

  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, states, log and any files needing persistency.

  Ports

  Here is the list of ports used by the container.

  When using the default bridge network, ports can be mapped to the host via the -p parameter (one per port mapping). Each mapping is defined with the following format: <HOST_PORT>:<CONTAINER_PORT>. The port number used inside the container might not be changeable, but you are free to use any port on the host side.

  See the Docker Container Networking documentation for more details.

  Port	Protocol	Mapping to host	Description
  5800	TCP	Optional	Port to access the application's GUI via the web interface. Mapping to the host is optional if access through the web interface is not wanted. For a container not using the default bridge network, the port can be changed with the WEB_LISTENING_PORT environment variable.
  5900	TCP	Optional	Port to access the application's GUI via the VNC protocol. Mapping to the host is optional if access through the VNC protocol is not wanted. For a container not using the default bridge network, the port can be changed with the VNC_LISTENING_PORT environment variable.

  Changing Parameters of a Running Container

  As can be seen, environment variables, volume and port mappings are all specified while creating the container.

  The following steps describe the method used to add, remove or update parameter(s) of an existing container. The general idea is to destroy and re-create the container:

  1. Stop the container (if it is running):

  docker stop chrome

  2. Remove the container:

  docker rm chrome

  3. Create/start the container using the docker run command, by adjusting parameters as needed.

  [!NOTE] Since all application's data is saved under the /config container folder, destroying and re-creating a container is not a problem: nothing is lost and the application comes back with the same state (as long as the mapping of the /config folder remains the same).

  Docker Compose File

  Here is an example of a docker-compose.yml file that can be used with Docker Compose.

  Make sure to adjust according to your needs. Note that only mandatory network ports are part of the example.

  version: '3'
  services:
    chrome:
      image: ghcr.io/wowmarcomei/docker-chrome:20240911
      ports:
        - "5800:5800"
      volumes:
        - "/docker/appdata/chrome:/config:rw"

  Accessing the GUI

  Assuming that container's ports are mapped to the same host's ports, the graphical interface of the application can be accessed via:

  • A web browser:

  http://<HOST IP ADDR>:5800
  

  • Any VNC client:

  <HOST IP ADDR>:5900
  

  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.

  SSVNC

  SSVNC is a VNC viewer that adds encryption security to VNC connections.

  While the Linux version of SSVNC works well, the Windows version has some issues. At the time of writing, the latest version 1.0.30 is not functional, as a connection fails with the following error:

  ReadExact: Socket error while reading
  

  However, for your convenience, an unofficial and working version is provided here:

  https://github.com/jlesage/docker-baseimage-gui/raw/master/tools/ssvnc_windows_only-1.0.30-r1.zip

  The only difference with the official package is that the bundled version of stunnel has been upgraded to version 5.49, which fixes the connection problems.

  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.

  [!TIP] 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 contain 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 the 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.

  [!CAUTION] Password is limited to 8 characters. This limitation comes from the Remote Framebuffer Protocol RFC (see section 7.2.2). Any characters beyond the limit are ignored.

  Web Authentication

  Access to the application's GUI via a web browser can be protected with a login page. When web authentication is enabled, users have to provide valid credentials, otherwise access is denied.

  Web authentication can be enabled by setting the WEB_AUTHENTICATION environment variable to 1.

  See the Environment Variables section for more details on how to set an environment variable.

  [!IMPORTANT] Secure connection must also be enabled to use web authentication. See the Security section for more details.

  Configuring Users Credentials

  Two methods can be used to configure users credentials:

  1. Via container environment variables.
  2. Via password database.

  Containers environment variables can be used to quickly and easily configure a single user. Username and pasword are defined via the following environment variables:

  • WEB_AUTHENTICATION_USERNAME
  • WEB_AUTHENTICATION_PASSWORD

  See the Environment Variables section for more details on how to set an environment variable.

  The second method is more secure and allows multiple users to be configured. The usernames and password hashes are saved into a password database, located at /config/webauth-htpasswd inside the container. This database file has the same format as htpasswd files of the Apache HTTP server. Note that password themselves are not saved into the database, but only their hash. The bcrypt password hashing function is used to generate hashes.

  Users are managed via the webauth-user tool included in the container:

  • To add a user password: docker exec -ti <container name or id> webauth-user add <username>.
  • To update a user password: docker exec -ti <container name or id> webauth-user update <username>.
  • To remove a user: docker exec <container name or id> webauth-user del <username>.
  • To list users: docker exec <container name or id> webauth-user user.