# Docker container for Firefox [![Docker Image Size](https://img.shields.io/microbadger/image-size/jlesage/firefox)](http://microbadger.com/#/images/jlesage/firefox) [![Build Status](https://drone.le-sage.com/api/badges/jlesage/docker-firefox/status.svg)](https://drone.le-sage.com/jlesage/docker-firefox) [![GitHub Release](https://img.shields.io/github/release/jlesage/docker-firefox.svg)](https://github.com/jlesage/docker-firefox/releases/latest) [![Donate](https://img.shields.io/badge/Donate-PayPal-green.svg)](https://paypal.me/JocelynLeSage/0usd) This is a Docker container for [Firefox](https://www.mozilla.org/en-US/firefox/). 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. --- [![Firefox logo](https://images.weserv.nl/?url=raw.githubusercontent.com/jlesage/docker-templates/master/jlesage/images/firefox-icon.png&w=200)](https://www.mozilla.org/en-US/firefox/)[![Firefox](https://dummyimage.com/400x110/ffffff/575757&text=Firefox)](https://www.mozilla.org/en-US/firefox/) Mozilla Firefox is a free and open-source web browser developed by Mozilla Foundation and its subsidiary, Mozilla Corporation. --- ## Table of Content * [Docker container for Firefox](#docker-container-for-firefox) * [Table of Content](#table-of-content) * [Quick Start](#quick-start) * [Usage](#usage) * [Environment Variables](#environment-variables) * [Data Volumes](#data-volumes) * [Ports](#ports) * [Changing Parameters of a Running Container](#changing-parameters-of-a-running-container) * [Docker Compose File](#docker-compose-file) * [Docker Image Update](#docker-image-update) * [Synology](#synology) * [unRAID](#unraid) * [User/Group IDs](#usergroup-ids) * [Accessing the GUI](#accessing-the-gui) * [Security](#security) * [SSVNC](#ssvnc) * [Certificates](#certificates) * [VNC Password](#vnc-password) * [Reverse Proxy](#reverse-proxy) * [Routing Based on Hostname](#routing-based-on-hostname) * [Routing Based on URL Path](#routing-based-on-url-path) * [Shell Access](#shell-access) * [Increasing Shared Memory Size](#increasing-shared-memory-size) * [Allowing the membarrier System Call](#allowing-the-membarrier-system-call) * [Sound Support](#sound-support) * [Setting Firefox Preferences Via Environment Variables](#setting-firefox-preferences-via-environment-variables) * [Troubleshooting](#troubleshooting) * [Crashes](#crashes) * [Support or Contact](#support-or-contact) ## Quick Start **NOTE**: The Docker command provided in this quick start is given as an example and parameters should be adjusted to your need. Launch the Firefox docker container with the following command: ``` docker run -d \ --name=firefox \ -p 5800:5800 \ -v /docker/appdata/firefox:/config:rw \ --shm-size 2g \ jlesage/firefox ``` Where: - `/docker/appdata/firefox`: This is where the application stores its configuration, log and any files needing persistency. Browse to `http://your-host-ip:5800` to access the Firefox GUI. ## Usage ``` docker run [-d] \ --name=firefox \ [-e =]... \ [-v :[:PERMISSIONS]]... \ [-p :]... \ --shm-size VALUE \ jlesage/firefox ``` | 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](#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](#data-volumes) section for more details. | | -p | Set a network port mapping (exposes an internal container port to the host). See the [Ports](#ports) section for more details. | | --shm-size | Set the size of `/dev/shm` to `VALUE`. The format of `VALUE` is ``, where `number` must be greater than `0` and `unit` can be `b` (bytes), `k` (kilobytes), `m` (megabytes), or `g` (gigabytes). **NOTE**: To avoid crashes, it is recommended to set this value to `2g`. | ### 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 | Description | Default | |----------------|----------------------------------------------|---------| |`USER_ID`| ID of the user the application runs as. See [User/Group IDs](#usergroup-ids) to better understand when this should be set. | `1000` | |`GROUP_ID`| ID of the group the application runs as. See [User/Group IDs](#usergroup-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 a 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 deleted 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 a web browser or VNC client). See the [Security](#security) section for more details. | `0` | |`VNC_PASSWORD`| Password needed to connect to the application's GUI. See the [VNC Password](#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` | ### 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: `:[:PERMISSIONS]`. | Container path | Permissions | Description | |-----------------|-------------|-------------| |`/config`| rw | This is where the application stores its configuration, log and any files needing persistency. | ### 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: `:`. 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. | ### 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 firefox ``` 2. Remove the container: ``` docker rm firefox ``` 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](https://docs.docker.com/compose/overview/). Make sure to adjust according to your needs. Note that only mandatory network ports are part of the example. ```yaml version: '3' services: firefox: image: jlesage/firefox build: . ports: - "5800:5800" volumes: - "/docker/appdata/firefox:/config:rw" ``` ## Docker Image Update Because features are added, issues are fixed, or simply because a new version of the containerized application is integrated, the Docker image is regularly updated. Different methods can be used to update the Docker image. The system used to run the container may have a built-in way to update containers. If so, this could be your primary way to update Docker images. An other way is to have the image be automatically updated with [Watchtower]. Whatchtower is a container-based solution for automating Docker image updates. This is a "set and forget" type of solution: once a new image is available, Watchtower will seamlessly perform the necessary steps to update the container. Finally, the Docker image can be manually updated with these steps: 1. Fetch the latest image: ``` docker pull jlesage/firefox ``` 2. Stop the container: ``` docker stop firefox ``` 3. Remove the container: ``` docker rm firefox ``` 4. Create and start the container using the `docker run` command, with the the same parameters that were used when it was deployed initially. [Watchtower]: https://github.com/containrrr/watchtower ### Synology For owners of a Synology NAS, the following steps can be used to update a container image. 1. Open the *Docker* application. 2. Click on *Registry* in the left pane. 3. In the search bar, type the name of the container (`jlesage/firefox`). 4. Select the image, click *Download* and then choose the `latest` tag. 5. Wait for the download to complete. A notification will appear once done. 6. Click on *Container* in the left pane. 7. Select your Firefox container. 8. Stop it by clicking *Action*->*Stop*. 9. Clear the container by clicking *Action*->*Clear*. This removes the container while keeping its configuration. 10. Start the container again by clicking *Action*->*Start*. **NOTE**: The container may temporarily disappear from the list while it is re-created. ### unRAID For unRAID, a container image can be updated by following these steps: 1. Select the *Docker* tab. 2. Click the *Check for Updates* button at the bottom of the page. 3. Click the *update ready* link of the container to be updated. ## 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 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. ## 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://:5800 ``` * Any VNC client: ``` :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](#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]: http://www.karlrunge.com/x11vnc/ssvnc.html ### 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.| **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 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. **ATTENTION**: Password is limited to 8 characters. This limitation comes from the Remote Framebuffer Protocol [RFC](https://tools.ietf.org/html/rfc6143) (see section [7.2.2](https://tools.ietf.org/html/rfc6143#section-7.2.2)). Any characters beyond the limit are ignored. ## Reverse Proxy The following sections contain NGINX configurations 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 `firefox.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 docker-firefox { # 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 firefox.domain.tld; location / { proxy_pass http://docker-firefox; } location /websockify { proxy_pass http://docker-firefox; 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/firefox` 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 docker-firefox { # 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 = /firefox {return 301 $scheme://$http_host/firefox/;} location /firefox/ { proxy_pass http://docker-firefox/; location /firefox/websockify { proxy_pass http://docker-firefox/websockify/; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection $connection_upgrade; proxy_read_timeout 86400; } } } ``` ## Shell Access To get shell access to 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. `crashplan-pro`). ## Increasing Shared Memory Size To prevent crashes from happening when running Firefox inside a Docker container, the size of the shared memory located at `/dev/shm` must be increased. The issue is documented [here]. By default, the size is 64MB, which is not enough. It is recommended to use a size of 2GB. This value is arbitrary, but known to work well. Setting the size of `/dev/shm` can be done via two method: - By adding the `--shm-size 2g` parameter to the `docker run` command. See the [Usage](#usage) section for more details. - By using shared memory of the host, by mapping `/dev/shm` via the parameter `-v /dev/shm:/dev/shm` of the `docker run` command. ## Allowing the membarrier System Call To properly work, recent versions of Firefox need the `membarrier` system call. Without it, tabs would frequently crash. Docker uses [seccomp profile] to restrict system calls available to the container. Before Docker version `20.03.0`, the `membarrier` system call was not allowed in the default profile. If you run a such version, you can use one of the following solutions, from the most to the least secure, to provide the container permission to use this sytem call: 1. Run the container with a custom seccomp profile allowing the `membarrier` system call. The [latest official seccomp profile] can be used. Download the file and then add the following parameter when creating the container: `--security-opt seccomp=/path/to/seccomp_profile.json`. 2. Run the container without the default seccomp profile (thus allowing all system calls). Use the following parameter when creating the container: `--security-opt seccomp=unconfined`. 3. Run the container in privileged mode. This effectively disables usage of seccomp. Add the `--privileged` parameter when creating the container. ## Sound Support For Firefox to be able to use the audio device available on the host, `/dev/snd` must be exposed to the container by adding the `--device /dev/snd` parameter to the `docker run` command. ## Setting Firefox Preferences Via Environment Variables Firefox preferences can be set via environment variables passed to the container. During the startup, a script process all these variables and modify the preference file accordingly. The name of the environment variable must start with `FF_PREF_`, followed by a string of your choice. For example, `FF_PREF_MY_PREF` is a valid name. The content of the variable should be in the format `NAME=VAL`, where `NAME` is the name of the preference (as found in the `about:config` page) and `VAL` is its value. A value can be one of the following types: - string - integer - boolean It is important to note that a value of type `string` should be surrounded by double quotes. Other types don't need them. For example, to set the `network.proxy.http` preference, one would pass the environment variable to the container by adding the following argument to the `docker run` command: ``` -e "FF_PREF_HTTP_PROXY=network.proxy.http=\"proxy.example.com\"" ``` If a preference needs to be *removed*, its value should be set to `UNSET`. For example: ``` -e "FF_PREF_HTTP_PROXY=network.proxy.http=UNSET" ``` **NOTE**: This is an advanced usage and it is recommended to set preferences via Firefox directly. ## Troubleshooting ### Crashes If Firefox is crashing frequently, make sure that: - The size of the shared memory located at `/dev/shm` has been increased. See the [Increasing Shared Memory Size](#increasing-shared-memory-size) section for more details. - The `membarrier` system call is not blocked by Docker. See the [Allowing the membarrier System Call](#allowing-the-membarrier-system-call) for more details. - Make sure the kernel of your Linux distribution is up-to-date. [TimeZone]: http://en.wikipedia.org/wiki/List_of_tz_database_time_zones [here]: https://bugzilla.mozilla.org/show_bug.cgi?id=1338771#c10 [seccomp profile]: https://docs.docker.com/engine/security/seccomp/ [latest official seccomp profile]: https://github.com/moby/moby/blob/master/profiles/seccomp/default.json ## Support or Contact Having troubles with the container or have questions? Please [create a new issue]. For other great Dockerized applications, see https://jlesage.github.io/docker-apps. [create a new issue]: https://github.com/jlesage/docker-firefox/issues