Dockerized rTorrent

About

Alpine docker image with vanilla rTorrent and ruTorrent. Built on top the excellent work done by crazy-max.

Features

• Multi-platform compact image
• Provides flexibility with download folder structure, compatible with Sonarr/Radarr
• Latest vanilla rTorrent and libTorrent
• Latest ruTorrent release
• Supervised by s6 v3
• Domain name resolving enhancements with c-ares for asynchronous DNS requests
• Enhanced rTorrent config and bootstraping with a local config
• XMLRPC through nginx over SCGI socket (basic auth optional)
• Excludes _cloudflare/mediainfo/screenshots ruTorrent plugins in order to make the image smaller
• Ability to add a custom ruTorrent plugin / theme
• Allow persisting specific configuration for ruTorrent plugins
• mktorrent for ruTorrent create plugin
• dumptorrent for automations that might need torrent metadata

---

• Managing download location
• Build locally
• Image
• Environment variables
  • General
  • rTorrent
  • ruTorrent
• Volumes
• Ports
• Usage
  • Command line
  • Docker Compose
  • Quadlet
• Notes
  • Populate .htpasswd files
  • Bootstrap config .rtlocal.rc
  • Override or add a ruTorrent plugin/theme
  • Edit a ruTorrent plugin configuration
  • Increase Docker timeout to allow rTorrent to shutdown gracefully
  • WAN IP address
  • Configure rTorrent session saving
  • Configure rTorrent send receive buffers
  • Configure rTorrent disk space preallocation
• License

Managing download location

This image does not explicitly require you to mount a /download folder. It's up to you to decide how do you want to manage download locations. If you're using *arr stack (sonarr/radarr), you should follow the same media library mount path everywhere in order to make them all work together nicely. Let's consider example:

media/
├─ downloads/
├─ library/
│  ├─ movies/
│  ├─ tv/
│  ├─ music/
│  ├─ ...

You would need to mount the /media volume to rtorrent/sonarr/radarr images the same way:

rtorrent
...
  -v /home/user/rtorrent:/data
  -v /home/user/rtorrent/passwd:/passwd
  -v /media:/media

and sonarr container

sonarr
...
  -v /home/user/sonarr:/data
  -v /media:/media

And finally, don't forget to set the default download dir RT_DEFAULT_DIR for rTorrent, in the example above it would be RT_DEFAULT_DIR=/media/downloads.

Build locally

git clone https://github.com/drrako/dockerized-rtorrent.git
cd dockerized-rtorrent
docker build -t drrako/rtorrent .

Image

Registry	Image
Docker Hub	drrako/rtorrent

Following platforms for this image are available:

linux/amd64
linux/arm/v7
linux/arm64

Environment variables

General

Variable Name	Description	Default Value
TZ	The timezone assigned to the container	UTC
PUID	rTorrent user id	1000
PGID	rTorrent group id	1000
WAN_IP	Public IP address reported to the tracker	(auto if empty)
WAN_IP_CMD	Command to resolve the Public IP address
MEMORY_LIMIT	PHP memory limit	256M
UPLOAD_MAX_SIZE	Upload max size	16M
CLEAR_ENV	Clear environment in FPM workers	yes
OPCACHE_MEM_SIZE	PHP OpCache memory consumption	128
MAX_FILE_UPLOADS	The maximum number of files allowed to be uploaded simultaneously	50
AUTH_DELAY	The time in seconds to wait for Basic Auth	0s
REAL_IP_FROM	Trusted addresses that are known to send correct replacement addresses	0.0.0.0/32
REAL_IP_HEADER	Request header field whose value will be used to replace the client address	X-Forwarded-For
LOG_ACCESS	Output access log	true
XMLRPC_AUTHBASIC_STRING	Message displayed during validation of XMLRPC Basic Auth	rTorrent XMLRPC restricted access
XMLRPC_PORT	XMLRPC port through nginx over SCGI socket	8000
XMLRPC_SIZE_LIMIT	Maximum body size of XMLRPC calls	4M
RUTORRENT_AUTHBASIC_STRING	Message displayed during validation of ruTorrent Basic Auth	ruTorrent restricted access
RUTORRENT_PORT	ruTorrent HTTP port	8080

Nginx

Variable Name	Description	Default Value
LOG_IP_VAR	Use another variable to retrieve the remote IP address for access log_format on Nginx	remote_addr
NGINX_WORKER_PROCESSES	Number of nginx worker processes	2 (set auto to utilize all cores)
NGINX_WORKER_CONNECTIONS	Number of nginx worker connections	1024

rTorrent

Variable Name	Description	Default Value
RT_DEFAULT_DIR	Sets the default download directory	/downloads
RT_LOG_LEVEL	rTorrent log level	info
RT_LOG_EXECUTE	Log executed commands to /data/rtorrent/log/execute.log	false
RT_LOG_XMLRPC	Log XMLRPC queries to /data/rtorrent/log/xmlrpc.log	false
RT_SESSION_SAVE_SECONDS	Seconds between writing torrent information to disk	3600
RT_TRACKER_DELAY_SCRAPE	Delay tracker announces at startup	true
RT_DHT_PORT	DHT UDP port (dht.port.set)	6881
RT_INC_PORT	Incoming connections (network.port_range.set)	50000
RT_SEND_BUFFER_SIZE	Sets default tcp wmem value (network.send_buffer.size.set)	4M
RT_RECEIVE_BUFFER_SIZE	Sets default tcp rmem value (network.receive_buffer.size.set)	4M
RT_PREALLOCATE_TYPE	Sets the type of disk space preallocation	0

ruTorrent

Variable Name	Description	Default Value
RU_REMOVE_CORE_PLUGINS	Comma separated list of core plugins to remove, set to false to disable removal
RU_HTTP_USER_AGENT	ruTorrent HTTP user agent	(provided by ruTorrent config)
RU_HTTP_TIME_OUT	ruTorrent HTTP timeout in seconds	30
RU_HTTP_USE_GZIP	Use HTTP Gzip compression	true
RU_RPC_TIME_OUT	ruTorrent RPC timeout in seconds	5
RU_LOG_RPC_CALLS	Log ruTorrent RPC calls	false
RU_LOG_RPC_FAULTS	Log ruTorrent RPC faults	true
RU_PHP_USE_GZIP	Use PHP Gzip compression	false
RU_PHP_GZIP_LEVEL	PHP Gzip compression level	2
RU_SCHEDULE_RAND	Rand for schedulers start, +0..X seconds	10
RU_LOG_FILE	ruTorrent log file path for errors messages	/data/rutorrent/rutorrent.log
RU_DO_DIAGNOSTIC	ruTorrent diagnostics like permission checking	true
RU_CACHED_PLUGIN_LOADING	Set to true to enable rapid cached loading of ruTorrent plugins	false
RU_SAVE_UPLOADED_TORRENTS	Save torrents files added via ruTorrent in /data/rutorrent/share/torrents	true
RU_OVERWRITE_UPLOADED_TORRENTS	Existing .torrent files will be overwritten	false
RU_FORBID_USER_SETTINGS	If true, allows for single user style configuration, even with webauth	false
RU_LOCALE	Set default locale for ruTorrent	UTF8

Volumes

• /data: rTorrent / ruTorrent config, session files, log, ...
• /passwd: Contains htpasswd files for basic auth

⚠️ Note that the volumes should be owned by the user/group with the specified PUID and PGID. If you don't give the volumes correct permissions, the container may not start.

Ports

• 6881 (or RT_DHT_PORT): DHT UDP port (dht.port.set)
• 8000 (or XMLRPC_PORT): XMLRPC port through nginx over SCGI socket
• 8080 (or RUTORRENT_PORT): ruTorrent HTTP port
• 50000 (or RT_INC_PORT): Incoming connections (network.port_range.set)

⚠️ Port p+1 defined for XMLRPC_PORT and RUTORRENT_PORT will also be reserved for healthcheck. (e.g. if you define RUTORRENT_PORT=8080, port 8081 will be reserved)

Usage

Command line

You can also use the following minimal command:

docker run --rm --name drrako-rtorrent \
  --ulimit nproc=65535 \
  --ulimit nofile=32000:40000 \
  -p 6881:6881/udp \
  -p 8000:8000 \
  -p 8080:8080 \
  -p 9000:9000 \
  -p 50000:50000 \
  -v $(pwd)/data:/data \
  -v $(pwd)/passwd:/passwd \
  -v $(pwd)/media/library:/media/library \
  drrako/rtorrent:latest

Docker Compose

Docker compose example can be found here.

docker compose up -d

Quadlet service

Quadlets really shine when it comes to managing dockerized services on small home servers, I really encourage you to give it a try instead of docker compose.

Adjust for your system and add the content below to /etc/containers/systemd/rtorrent.container

[Unit]
Description=rTorrent

[Container]
Image=docker.io/drrako/rtorrent:latest
StopTimeout=180
AutoUpdate=registry
Network=host
Environment=PUID=1000
Environment=PGID=1000
Environment=TZ=Etc/UTC
Environment=RT_DEFAULT_DIR=/media/library/downloads
Environment=RT_DHT_PORT=6881
Environment=XMLRPC_PORT=8000
Environment=RT_INC_PORT=50000
Volume=/home/PUID_USER/rtorrent:/data
Volume=/home/PUID_USER/rtorrent/passwd:/passwd
Volume=/media/library:/media/library

[Service]
Restart=always
TimeoutStopSec=180

[Install]
WantedBy=multi-user.target

PUID user should have r/w access to /media/library folder.

Notes

Populate .htpasswd files

For ruTorrent basic auth and XMLRPC through nginx you can populate .htpasswd files with the following command:

docker run --rm -it httpd:2.4-alpine htpasswd -Bbn <username> <password> >> $(pwd)/passwd/rutorrent.htpasswd

Htpasswd files used:

• rpc.htpasswd: XMLRPC through nginx
• rutorrent.htpasswd: ruTorrent basic auth

Bootstrap config .rtlocal.rc

When rTorrent is started the bootstrap config /etc/rtorrent/.rtlocal.rc is imported. This configuration cannot be changed unless you rebuild the image or overwrite these elements in your .rtorrent.rc. Here are the particular properties of this file:

• system.daemon.set = true: Launcher rTorrent as a daemon
• A config layout for the rTorrent's instance you can use in your .rtorrent.rc:
  • cfg.basedir: Home directory of rtorrent (/data/rtorrent/)
  • cfg.logs: Logs directory (/data/rtorrent/log/)
  • cfg.session: Session directory (/data/rtorrent/.session/)
  • cfg.rundir: Runtime data of rtorrent (/var/run/rtorrent/)
• d.data_path: Config var to get the full path of data of a torrent (workaround for the possibly empty d.base_path attribute)
• directory.default.set: Default directory to save the downloaded torrents, set RT_DEFAULT_DIR env variable
• session.path.set: Default session directory (cfg.session)
• PID file to /var/run/rtorrent/rtorrent.pid
• network.scgi.open_local: SCGI local socket and make it group-writable and secure
• network.port_range.set: Listening port for incoming peer traffic (50000-50000)
• dht.port.set: UDP port to use for DHT (6881)
• log.open_file: Default logging to /data/rtorrent/log/rtorrent.log
  • Log level can be modified with the environment variable RT_LOG_LEVEL
  • rpc_events are logged be default
  • To log executed commands, add the environment variable RT_LOG_EXECUTE
  • To log XMLRPC queries, add the environment variable RT_LOG_XMLRPC

Override or add a ruTorrent plugin/theme

You can add a plugin for ruTorrent in /data/rutorrent/plugins/. If you add a plugin that already exists in ruTorrent, it will be removed from ruTorrent core plugins and yours will be used. And you can also add a theme in /data/rutorrent/themes/. The same principle as for plugins will be used if you want to override one.

⚠️ container has to be restarted to apply changes

Edit a ruTorrent plugin configuration

Loading the configuration of a plugin is done via a conf.php file placed at the root of the plugin folder. To solve this issue with Docker, a special folder has been created in /data/rutorrent/plugins-conf to allow you to configure plugins. For example to configure the diskspace plugin, you will need to create the /data/rutorrent/plugins-conf/diskspace.php file with your configuration:

<?php

$diskUpdateInterval = 10;	  // in seconds
$notifySpaceLimit = 512;	  // in Mb
$partitionDirectory = null;	// if null, then we will check rtorrent download directory (or $topDirectory if rtorrent is unavailable)
				                    // otherwise, set this to the absolute path for checked partition. 

⚠️ container has to be restarted to apply changes

Increase Docker timeout to allow rTorrent to shutdown gracefully

After issuing a shutdown command, Docker waits 10 seconds for the container to exit before it is killed. If you are a seeding many torrents, rTorrent may be unable to gracefully close within that time period. As a result, rTorrent is closed forcefully and the lockfile isn't removed. This stale lockfile will prevent rTorrent from restarting until the lockfile is removed manually.

The timeout period can be extended by either adding the parameter -t XX to the docker command or stop_grace_period: XXs in compose.yml, where XX is the number of seconds to wait for a graceful shutdown.

WAN IP address

WAN_IP is the public IP address sent to the tracker. In the majority of cases you don't need to set it as it will be automatically determined by the tracker.

But it can be sometimes required to enforce the public IP address when you are behind a VPN where an erroneous IP is sometimes reported.

You can also use the WAN_IP_CMD environment variable to specify a command to resolve your public IP address. Here are some commands you can use:

• dig +short myip.opendns.com @resolver1.opendns.com
• curl -s ifconfig.me
• curl -s ident.me

Configure rTorrent session saving

RT_SESSION_SAVE_SECONDS is the seconds between writing torrent information to disk. The default is 3600 seconds which equals 1 hour. rTorrent has a bad default of 20 minutes. Twenty minutes is bad for the lifespan of SSDs and greatly reduces torrent throughput.

It is no longer possible to lose torrents added through ruTorrent on this docker container. Only torrent statistics are lost during a crash. (Ratio, Total Uploaded & Downloaded etc.)

Higher values will reduce disk usage, at the cost of minor stat loss during a crash. Consider increasing to 10800 seconds (3 hours) if running thousands of torrents.

rTorrent tracker delay scrape

RT_TRACKER_DELAY_SCRAPE specifies whether to delay tracker announces at rTorrent startup. The default value is true. There are two main benefits to keeping this feature enabled:

1. Software Stability: rTorrent will not crash or time-out with tens of thousands of trackers.
2. Immediate Access: ruTorrent can be accessed immediately after rTorrent is started.

rTorrent send receive buffers

Overriding the default TCP rmem and wmem values for rTorrent improves torrent throughput.

• RT_SEND_BUFFER_SIZE: Sets default tcp wmem value for the socket.
• RT_RECEIVE_BUFFER_SIZE: Sets default tcp rmem value for the socket.

Recommended values:

• 2GB of less system memory: Reduce to 1M send and 1M receive regardless of speed.
• 4GB to 16GB of system memory: Keep at default values of 4M send and 4M receive.
• 16GB to 32GB of system memory: Increase to 8M send for 500Mbps speeds.
• 32GB to 64GB of system memory: Increase to 16M send for 1G speeds.
• 64GB to 128GB of system memory: Increase to 32M send for 2.5G speeds.
• 128GB to 256GB of system memory: Increase to 64M send for 10G speeds.

Memory is better spent elsewhere except under limited circumstances for high memory and speed conditions. The default values should not be increased, unless both the memory and speed requirements are met. These values of system memory are also recommended based on the port speed for rTorrent to reduce disk usage.

rTorrent disk space preallocation

Preallocate disk space for contents of a torrent

• RT_PREALLOCATE_TYPE: Sets the type of disk space preallocation to use.

Acceptable values:

• 0 = disabled (default value)
• 1 = enabled, allocate when a file is opened for write
• 2 = enabled, allocate space for the whole torrent at once

This feature is disabled by default becuase it only benefits HDDs. By allocating files in sequence we can increase the read speed for seeding.

The first type "1" only allocates disk space for files which start downloading. Use where disk space is more important than speed. Or you intend to download selective torrent files.

The second type "2" allocates disk space for the entire torrent, whether it's downloaded or not. This method is faster than "1" becuase it reduces random reads for the entire torrent. Use where speed is more important than disk space. Or you intend to download 100% of every torrent.

License

MIT. See LICENSE for more details.