Monolithic Game Download Cache Docker Container

Introduction

This docker container provides a caching proxy server for game download content. For any network with more than one PC gamer in connected this will drastically reduce internet bandwidth consumption.

The primary use case is gaming events, such as LAN parties, which need to be able to cope with hundreds or thousands of computers receiving an unannounced patch - without spending a fortune on internet connectivity. Other uses include smaller networks, such as Internet Cafes and home networks, where the new games are regularly installed on multiple computers; or multiple independent operating systems on the same computer.

This container is designed to support any game that uses HTTP and also supports HTTP range requests (used by Origin). This should make it suitable for:

• Steam (Valve)
• Origin (EA Games)
• Riot Games (League of Legends)
• Battle.net (Hearthstone, Starcraft 2, Overwatch)
• Frontier Launchpad (Elite Dangerous, Planet Coaster)
• Uplay (Ubisoft)
• Windows Updates

This is the best container to use for all game caching and should be used for Steam in preference to the steamcache/steamcache and steamcache/generic containers.

Usage

You need to be able to redirect HTTP traffic to this container. The easiest way to do this is to replace the DNS entries for the various game services with your cache server.

You can use the steamcache-dns docker image to do this or you can use a DNS service already on your network see the steamcache-dns github page for more information.

For the cache files to persist you will need to mount a directory on the host machine into the container. You can do this using -v <path on host>:/data/cache. You can do the same with a logs directory as well if you want logs to be persistent as well.

Run the container using the following to allow TCP port 80 (HTTP) and to mount /cache/steam/data directory into the container.

docker run \
  --restart unless-stopped \
  --name lancache \
  -v /cache/data:/data/cache \
  -v /cache/logs:/data/logs \
  -p 192.168.1.10:80:80 \
  steamcache/monolithic:latest

Unlike steamcache/generic this service will cache all cdn services (defined in the uklans cache-domains repo so multiple instances are not required

Simple Full Stack startup

To initialise a full caching setup with dns and sni proxy you can use the following script as a starting point:

export HOST_IP=`hostname -I | cut -d' ' -f1`
docker run --restart unless-stopped --name steamcache-dns --detach -p 53:53/udp -e USE_GENERIC_CACHE=true -e LANCACHE_IP=$HOST_IP steamcache/steamcache-dns:latest
docker run --restart unless-stopped --name lancache --detach -v /cache/data:/data/cache -v /cache/logs:/data/logs -p 80:80  steamcache/monolithic:latest
docker run --restart unless-stopped --name sniproxy --detach -p 443:443 steamcache/sniproxy:latest
echo Please configure your dhcp server to serve dns as $HOST_IP

Please check that hostname -I returns the correct IP before running this snippet

Changing from steamcache/steamcache and steamcache/generic

This new container is designed to replace an array of steamcache or generic containers with a single monolithic instance. However if you currently run a steamcache or generic setup then there a few things to note

1. Your existing cache files are NOT compatible with steamcache/monolithic, unfortunately your cache will need repriming
2. You do not need multiple containers, a single monolithic container will cache ALL cdns without collision
3. steamcache/monolithic should be compatible with your existing container's env vars so you can use the same run command you currently use, just change to steamcache/monolithic

Origin and SSL

Some publishers, including Origin, use the same hostnames we're replacing for HTTPS content as well as HTTP content. We can't cache HTTPS traffic, so if you're intercepting DNS, you will need to run an SNI Proxy container on port 443 to forward on any HTTPS traffic.

docker run \
  --restart unless-stopped \
  --name sniproxy \
  -p 443:443 \
  steamcache/sniproxy:latest

Please read the steamcache/sniproxy project for more information.

DNS Entries

You can find a list of domains you will want to use for each service over on uklans/cache-domains. The aim is for this to be a definitive list of all domains you might want to cache.

Suggested Hardware

Regular commodity hardware (a single 2TB WD Black on an HP Microserver) can achieve peak throughputs of 30MB/s+ using this setup (depending on the specific content being served).

Changing Upstream DNS

If you need to change the upstream DNS server the cache uses, these are defined by the UPSTREAM_DNS environment variable. The defaults are Google DNS (8.8.8.8 and 8.8.4.4).

 UPSTREAM_DNS 8.8.8.8 8.8.4.4

You can override these using the -e argument to docker run and specifying your upstream DNS servers. Multiple upstream dns servers are allowed, separated by whitespace.

-e UPSTREAM_DNS="1.1.1.1 1.0.0.1"

Tweaking Cache sizes

Two environment variables are available to manage both the memory and disk cache for a particular container, and are set to the following defaults.

CACHE_MEM_SIZE 500m
CACHE_DISK_SIZE 1000000m

In addition, there is an environment variable to control the max cache age

CACHE_MAX_AGE 3650d

You can override these at run time by adding the following to your docker run command. They accept the standard nginx notation for sizes (k/m/g/t) and durations (m/h/d)

-e CACHE_MEM_SIZE=4000m -e CACHE_DISK_SIZE=1000g

Tuning your cache

Steam in particular has some inherrent limitations caused by the adherence to the HTTP spec connection pool. As such steam download speed are highly dependent on the latency between your server and the steam cdn servers. In the event you find your initial download speed with the default settings is slow this can be resolved by allocating more IP's to your ache. We suggest adding one IP at a time to see how much gain can be had (4 seems to work for a number of people)

Step 1: Adding IP's to your docker host

Consult your OS documentation in order to add additional IP addresses onto your docker cache host machine

Step 2: Adding IP's to your cache container

In order for this to work you need to add the port maps onto the relevant cdn container (for example steam).

• If you are using steamcache/monolithic then using -p 80:80 should be sufficient as per the documentation.
• If you are using steamcache/generic or steamcache/steamcache then add multiple -p <IPadddress>:80:80 for each IP you have added. For example -p 10.10.1.30:80:80 -p 10.10.1.31:80:80

Step 3: Informing steamcache-dns of the extra IP's

Finally we need to inform steamcache-dns that STEAM is now available on multiple IP addresses. This can be done on the command line using the following command -e STEAMCACHE_IP="10.10.1.30 10.10.1.31". Note the quotes surrounding the multiple IP addresses.

Step 4: Testing

Choose a game which has not been seen by the cache before (or clear your /data/cache folder) and start it downloading. Check to see what the maximum speed seen by your steam client is. If necessary repeat steps 1-3 with additional IPs until you see a download equivalent to your uncached steam client or no longer see an improvement vs the previous IP allocation.

Monitoring

Access logs are written to /data/logs. If you don't particularly care about keeping them, you don't need to mount an external volume into the container.

You can tail them using:

docker exec -it lancache tail -f /data/logs/access.log

If you have mounted the volume externally then you can tail it on the host instead.

Advice to Publishers

If you're a games publisher and you'd like LAN parties, gaming centers and other places to be able to easily cache your game updates, we reccomend the following:

• If your content downloads are on HTTPS, you can do what Riot have done - try and resolve a specific hostname. If it resolves to a RFC1918 private address, switch your downloads to use HTTP instead.
• Try to use hostnames specific for your HTTP download traffic.
• Tell us the hostnames that you're using for your game traffic. We're maintaining a list at uklans/cache-domains and we'll accept pull requests!
• Have your client verify the files and ensure the file they've downloaded matches the file they should have downloaded. This cache server acts as a man-in-the-middle so it would be good to ensure the files are correct.

If you need any further advice, please contact us and we'll be glad to help!

Frequently Asked Questions

If you have any questions, please check our FAQs. If this doesn't answer your question, please raise an issue in GitHub.

Thanks

• Based on original configs from ansible-lanparty.
• Everyone on /r/lanparty who has provided feedback and helped people with this.
• UK LAN Techs for all the support.

License

The MIT License (MIT)

Copyright (c) 2019 Jessica Smith, Robin Lewis, Brian Wojtczak, Jason Rivers, James Kinsman

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.