[Dnsmasq-discuss] OS X hosted dnsmasq for AD SRV records

[Peet McKinney]

Yes, load balancing is my goal.  As it stands now, only one server is being used as a GC by OS X clients when using my dnsmasq servers for DNS.  It's a robust server but would probably not scale very well.

Thanks.Peet

On Nov 22, 2010, at 2:44 PM, richardvoigt at gmail.com wrote:

> Don't know the answer to your question, just wanted to point out that
> your other server is not actually returning them in random order.
> They are always in the same order but are rotated, and typically
> subsequent queries rotate the list by one to achieve load balancing.
> 
> Is load balancing your goal?
> 
> On Mon, Nov 22, 2010 at 3:35 PM, Peet McKinney <lists at peetinc.com> wrote:
>> All,
>> 
>> dnsmasq has been an absolute life-saver in my environment. OS X Directory services isn't playing nicely with GC discovery in my Active Directory environment, so I've brought up a couple instances of dnsmasq to help force it into being a good citizen.
>> 
>> I've compiled dnsmasq on 10.6.4 from the 2.55 source and configured it to respond correctly to my SRV lookups. I've also installed the launchd plist. (Though I have to wonder the value of having that plist configured with '--log-queries' and '--log-facility=/var/log/dnsmasq.log' by default. Admittedly, I'm an idiot for not checking and ending up with a 24GB dnsmasq.log, but considering there's not a default rotation for the log it seems a bit of an odd choice for a default launchd setup.)
>> 
>> Since cleaning up my silly logging issues, I'm left with what my simply be a standard behavior of dnsmasq, but one that I'd really like to find a way around.  When I query SRV records that are in my dnsmasq config, they are *always* returned in the same order with no randomization. Please see below:
>> 
>> jodr:~ jadmin$ host -t SRV _gc._tcp.umontana.edu
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 dbsaddc3.dbsad.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 gsdc1.gs.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 gsdc0.gs.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 msodc13.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdc5.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdc2.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mitosdc2.missoula.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mitosdc0.missoula.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umontanadc2.umontana.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umontanadc1.umontana.edu.
>> 
>> When I lookup against the AD DNS servers they are randomized.  Of course the results below include servers that I don't want to see returned as results, but you can see that two lookups in quick succession  provided completely different answers:
>> 
>> j010-peet:~ jadmin$ host -t SRV _gc._tcp.umontana.edu
>> ;; Truncated, retrying in TCP mode.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umontanadc2.umontana.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdcctw.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mitosdc2.missoula.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mitosdc0.missoula.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 gsdc1.gs.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 flbs-dc01.flbsad.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umontanadc1.umontana.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 gsdc0.gs.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdccte.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 dbsaddc3.dbsad.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdc5.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdch1.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 msodc13.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdc2.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umh-st1.helena.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 dbsaddcfm.dbsad.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umh-ap1.helena.campus.
>> 
>> j010-peet:~ jadmin$ host -t SRV _gc._tcp.umontana.edu
>> ;; Truncated, retrying in TCP mode.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mitosdc2.missoula.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mitosdc0.missoula.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 gsdc1.gs.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 flbs-dc01.flbsad.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umontanadc1.umontana.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 gsdc0.gs.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdccte.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 dbsaddc3.dbsad.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdc5.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdch1.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 msodc13.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdcctw.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 mumtdc2.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umh-st1.helena.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 dbsaddcfm.dbsad.umt.edu.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umh-ap1.helena.campus.
>> _gc._tcp.umontana.edu has SRV record 0 100 3268 umontanadc2.umontana.edu.
>> 
>> Is there anyway to randomize the answers dnsmasq provides.
>> 
>> Thanks.Peet
>> 
>> 
>> 
>> 
>> 
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