Transmission with WebUI and OpenVPN

=== This Docker container lets you run Transmission with WebUI while connecting to either BTGUARD or PIA OpenVPN. When using PIA as provider it will update Transmission hourly with assigned open port. Please read the instructions below.

Run container from Docker registry

The container is available from the Docker registry and this is the simplest way to get it. To run the container use this command:

$ docker run --privileged  -d \
              -v /your/storage/path/:/data \
              -e "OPENVPN_PROVIDER=PIA" \
              -e "OPENVPN_CONFIG=Netherlands" \
              -e "OPENVPN_USERNAME=user" \
              -e "OPENVPN_PASSWORD=pass" \
              -p 9091:9091 \
              haugene/transmission-openvpn

The OPENVPN_PROVIDER and OPENVPN_CONFIG are optional variables. If no provider is given, it will default to PIA. If no config is given, a default config will be selected for the provider you have chosen. The only mandatory environment variables are your OpenVPN username and password. You must set the environment variables OPENVPN_USERNAME and OPENVPN_PASSWORD to the credentials given by your OpenVPN provider.

Find the OpenVPN configurations avaliable by looking in the openvpn folder of the GitHub repository.

As you can see, the container also expects a data volume to be mounted. It is used for storing your downloads from Transmission. The container comes with a default Transmission settings.json file that expects the folders completed, incomplete, and watch to be present in /your/storage/path (aka /data). This is where Transmission will store your downloads, incomplete downloads and a watch directory to look for new .torrent files.

Required environment options

Variable	Function	Example
OPENVPN_USERNAME	Your OpenVPN username	OPENVPN_USERNAME=asdf
OPENVPN_PASSWORD	Your OpenVPN password	OPENVPN_PASSWORD=asdf

Network configuration options

Variable	Function	Example
OPENVPN_PROVIDER	Sets the OpenVPN provider to use.	OPENVPN_PROVIDER=BTGUARD
OPENVPN_CONFIG	Sets the OpenVPN endpoint to connect to.	OPENVPN_CONFIG=UK Southampton
RESOLV_OVERRIDE	The value of this variable will be written to /etc/resolv.conf.	RESOLV_OVERRIDE=nameserver 8.8.8.8\nnameserver 8.8.4.4\n

Transmission configuration options

You may override transmission options by setting the appropriate environment variable.

The environment variables are the same name as used in the transmission settings.json file and follow the format given in these examples:

Transmission variable name	Environment variable name
speed-limit-up	TRANSMISSION_SPEED_LIMIT_UP
speed-limit-up-enabled	TRANSMISSION_SPEED_LIMIT_UP_ENABLED
ratio-limit	TRANSMISSION_RATIO_LIMIT
ratio-limit-enabled	TRANSMISSION_RATIO_LIMIT_ENABLED

As you can see the variables are prefixed with TRANSMISSION_, the variable is capitalized, and - is converted to _.

PS: TRANSMISSION_BIND_ADDRESS_IPV4 will be overridden to the IP assigned to tunnel interface by PIA. This is to prevent leaking of the host IP.

Building the container yourself

To build this container, clone the repository and cd into it.

Build it:

$ cd /repo/location/docker-transmission-openvpn
$ docker build -t docker-transmission-openvpn .

Run it:

$ docker run --privileged  -d \
              -v /your/storage/path/:/data \
              -e "OPENVPN_PROVIDER=PIA" \
              -e "OPENVPN_CONFIG=Netherlands" \
              -e "OPENVPN_USERNAME=user" \
              -e "OPENVPN_PASSWORD=pass" \
              -p 9091:9091 \
              docker-transmission-openvpn

This will start a container as described in the "Run container from Docker registry" section. This means that you should have the folders "completed, incomplete and watch" in /your/storage/path, and pia-credentials.txt in /your/config/path.

Known issues

Some have encountered problems with DNS resolving inside the docker container. This causes trouble because OpenVPN will not be able to resolve the host to connect to. If you have this problem, please refer to issue #4 on GitHib and you might want to use the RESOLV_OVERRIDE flag described in "Network configuration options"

If you are having issues with this container please submit an issue on GitHub. Please provide logs, docker version and other information that can simplify reproducing the issue. Using the latest stable verison of Docker is always recommended. Support for older version is on a best-effort basis.

Access the WebUI

But what's going on? My http://my-host:9091 isn't responding? This is because the VPN is active, and since docker is running in a different ip range than your client the response to your request will be treated as "non-local" traffic and therefore be routed out through the VPN interface.

How to fix this

There are several ways to fix this. You can pipe and do fancy iptables or ip route configurations on the host and in the Docker image. But I found that the simplest solution is just to proxy my traffic. Start a Nginx container like this:

$ docker run -d -v /path/to/nginx.conf:/etc/nginx/nginx.conf:ro -p 8080:8080 nginx

Where /path/to/nginx.conf has this content:

events {
  worker_connections 1024;
}

http {
  server {
    listen 8080;
    location / {
      proxy_pass http://host.ip.address.here:9091;
    }
  }
}

Your Transmission WebUI should now be avaliable at "your.host.ip.addr:8080/transmission/web/". Change the port in the docker run command if 8080 is not suitable for you.

What if I want to run the container interactively.

If you want do have access inside the container while running you have two choices. To have a look inside an already running container, use docker exec to get a terminal inside the container.

$ docker ps | grep transmission-openvpn | awk '{print $1}' // Prints container id
$ af4dd385916d
$ docker exec -it af4dd bash

If you want to start the container without it starting OpenVPN on boot, then run the image without daemonizing and use bash as entrypoint.

$ docker run --privileged -it transmission-openvpn bash

From there you can start the service yourself, or do whatever (probably developer-related) you came to do.

Controlling Transmission remotely

The container exposes /config as a volume. This is the directory where the supplied transmission and PIA credentials will be stored. If you have transmission authentication enabled and want scripts in another container to access and control the transmission-daemon, this can be a handy way to access the credentials. For example, another container may pause or restrict transmission speeds while the server is streaming video.