[tor-bugs] #17359 [Tor]: __DisablePredictedCircuits causes bootstrap to hang at "Connecting to Tor Network"

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#17359: __DisablePredictedCircuits causes bootstrap to hang at "Connecting to Tor
Network"
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 Reporter:  teor    |          Owner:
     Type:  defect  |         Status:  new
 Priority:  Medium  |      Milestone:  Tor: 0.2.8.x-final
Component:  Tor     |        Version:
 Severity:  Minor   |     Resolution:
 Keywords:  tor-hs  |  Actual Points:
Parent ID:          |         Points:
  Sponsor:          |
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Changes (by teor):

 * keywords:   => tor-hs


Comment:

 Replying to [comment:2 arma]:
 > Hm! I think our definition of 100% bootstrapped is that we made a
 circuit. Is that so terrible a definition?

 It's an excellent definition. But we require 100% bootstrapped to make
 circuits in some configs, so it's a circular dependency (on hidden/onion
 services, and without predicted circuits). Perhaps a solution is to make
 introduction point connections dependent on 80%, not 100%? (This would
 also fix the scenario where each type of predicted circuit is disabled
 individually by a specific option.)

 > What situation is causing us to set DisablePredictedCircuits without a
 controller generating its own circuits? That is, is this just a
 pathological config, or is it actually a thing that somebody wants to do?

 It's useful for load-balancing hidden/onion service configurations like
 (Rendezvous) Single Onion Services (RSOS - #17178, SOS - prop#252), where
 (almost) every connection is one-hop, and several hundred tor instances
 might be running. In this case, predicted circuits will never be used
 (except for descriptor uploads, and not every instance uploads descriptors
 due to OnionBalance). Predicted circuits represent unnecessary load on the
 server and network in this case.

 > And lastly, be aware that "80% connecting to tor network" is the initial
 bootstrap message if you start Tor with enough cached dir info. That is,
 seeing 80% doesn't mean anything at all in this case about whether the
 network is plugged in.

 Indeed. I was using chutney on localhost, and it worked without
 !__DisablePredictedCircuits set, so I know the network was plugged in and
 chutney was working.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/17359#comment:3>
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