tree a28a9ea297b813ebb6647f113305f54ef17e5a93
parent e725dc164015d873b64639f0fee9ba5c30175f4c
author Pierre Imai <imaipi@google.com> 1456131041 +0900
committer Pierre Imai <imaipi@google.com> 1459824163 +0900

Ignore unreliable DNS servers.

Collect statistics about DNS query success state and delay. Ignore
servers that have been tried at least five times and have a success rate
of < 0.25. Retry these servers once every 180s.

Bug: 25731675
Change-Id: I78e24f43e388dca82fb81835e1796f4c7dce8da3