[tor-talk] Load Balancing/High Availability Hidden Services

[George Kadianakis]

MacLemon <tor at maclemon.at> writes:

> Hoi!
>
> I'm looking into ideas for creating “load balanced” or “high availability” hidden services. Mostly pertaining to web servers serving large-ish static files. (Let's say 5-100MB each.)
>
> Load balanced as in not all requests end up at the same box to speed up downloads.
> High availability as in the service is still available if one box goes down or is taken offline for maintenance.
>
> So, not exactly your usual distributed-cluster setup.
>
>
> From what I understand it would not make sense to run the same HS Key on multiple boxes since the descriptors would overwrite each other every few minutes.
>
> I don't think one can do something like Round-Robin DNS with HS.
>
> So the only way I can imagine this to work is a central redirection node that know about all the nodes and more or less intelligently/randomly 302 redirects each file request to a known-to-it server.
>
> This still leaves a single-point-of-failure in form of the redirection server but would at least distribute the traffic load across multiple servers and cope for nodes coming and going.
>
> Has anyone done something like this?
>

An application-layer load balancer like HAProxy might be able to help you.

Unfortunately, there is not something equivalent to DNS Round Robin
for hidden services yet. There are some ideas on how to do this on the
Introduction Point-layer, but a proposal still needs to be written. For
further reading:
https://lists.torproject.org/pipermail/tor-dev/2014-April/006788.html
https://lists.torproject.org/pipermail/tor-dev/2014-May/006812.html