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  1. Traffic Server
  2. TS-313

DNS and resolvers improvements



    • Improvement
    • Status: Closed
    • Minor
    • Resolution: Fixed
    • None
    • 2.1.4
    • DNS


      (was yahoo bug 1542263)

      Original description
      by Leif Hedstrom 2 years ago at 2007-10-16 17:00

      There are two options to configure/manage how TS finds resolvers via records.config:

      CONFIG proxy.config.dns.round_robin_nameservers INT 0
      CONFIG proxy.config.dns.nameservers STRING NULL

      Without these set, TS will simply "parse" /etc/resolv.conf, to find nameserver/resolver entries. This is
      fine. However, there are a few things that are "broken" or could be improved with the two options above:

      1) If you want to do "round robin" over your resolvers, you must also explicitly define the set of servers in
      the dns.nameservers config. There is no way to have it round robin over the default resolvers from /etc/resolv.conf.

      2) You can not set an explicit set of dns.nameservers, without also making them be used in a round robin fashion. This
      is highly undesirable for instance if you want to use a local resolver first (listening on, but fall
      back to a set of regular resolvers.

      3) Once listing explicit dns.nameservers, there is no way to have it also add the implicit resolvers from
      /etc/resolv.conf. It'd be very useful if you could "include" an external filename as part of the nameservers
      list, e.g.


      I'd suggest we separate the intertwined relationship between the two options, which would solve issues #1 and #2. As a
      bonus feature, we should be able to either implement the flexibility of #3, or at least make it possible (via a new
      config option) to include /etc/resolv.conf resolvers even when dns.nameservers is set.

      Marking this as an RFE, as it's not exactly a bug, but it's still somewhat critical for us to support this properly.

      Comment 1
      by Yung-Zen Lai 21 months ago at 2008-07-09 18:56:24

      Per issue #2, "proxy.config.dns.nameservers" config currently only works while setting "CONFIG
      proxy.config.dns.round_robin_nameservers INT 1". Even only one dns.nameservers is set. It seems not that make
      sense. ^^a


        1. TS-313-DNS_round_robin_and_failover_v2.patch
          17 kB
          Zhao Yongming
        2. TS-313-DNS_round_robin_and_failover_v1.patch
          18 kB
          Zhao Yongming
        3. TS-313-Interim.patch
          2 kB
          Jason Giedymin



            zwoop Leif Hedstrom
            mlibbey Miles Libbey
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