Bind Clustering

mlists at zoominternet.net mlists at zoominternet.net
Tue Aug 3 12:07:46 UTC 2010


 
 One thing you have top remember is the Slave NEVER updates the
Master.
 The updater is always the Master and the receiver is always the
Slave.
 I have posted about using 2 masters. You should be able to do a
search on he 
 archive and find the post.
 In short all you need to do is setup 2 masters and make them a slave
of the 
 other that way no matter which is updated everyone gets the update.
 On Thu 07/29/10  7:25 AM , "Gordon A. Lang" glang at goalex.com sent:
 I know BIND does not currently support multi-master.  And I
understand that 
 trying to strap together my own pseudo-multi-master implementation
using 
 BIND, bubble gum, and tape isn't a sustainable solution.  But,
nevertheless, 
 I don't really need a true multi-master implementation -- I just
need to 
 keep my backup master relatively up to date without relying on
frequent 
 freeze-copy-thaw operations.  I would be happy to have the updates
go to one 
 slave, and then be replicated to both the active master and the
backup 
 master.  I would deal with drift via brute force i.e. I would have
the 
 active master copy over to the backup master on a once or twice a
day basis, 
 not once every 5 minutes.
 I think it would be great if there were a new config construct added
whereby 
 the update-forward target(s) are explicitly specified.  In the case
where 
 the masters are slaves of a hidden master that is directly
reachable, it 
 would allow for the updates to be directly forwarded to the primary
master 
 instead of being forwarded twice.  And if multiple update-forward
targets 
 are specified, then all targets always get an update.  This could be
used to 
 maintain a duplicate (hidden) master and/or eliminate the
failure-delay when 
 the multiple masters "switch over," take turns being the master. 
And 
 possibly the specified update-forward target construct could also
have an 
 optional behavior of "forward-to-all" or "stop-on-first-success." if
current 
 behavior is preferred, but with a different list than then
zone-transfer 
 master list.
 Better yet, I would like add update-forwarding for master zones --
perhaps 
 it could be called update-replication.
 I guess what I would really like to see is multiple MNAME targets 
 accommodated right in the SOA, but I imagine that would have a
serious 
 compatibility challenge.
 Or else maybe a new zone type called backup-master that acts like a
slave 
 until an rndc control flips its operation state.
 I would like to get see some more comments on this.
 And I would really appreciate it if someone could tell me where in
the 
 source code I should look to find where the update-forward targets
are 
 obtained so that I can evaluate what it would take for me to write
my own 
 modifications.
 Thanks.
 --
 Gordon A. Lang
 ----- Original Message ----- 
 From: "Chris Buxton" 
 To: "Gordon A. Lang" ; 
 Sent: Wednesday, July 28, 2010 11:22 PM
 Subject: Re: Bind Clustering
 > Updates are always forwarded to the zone masters, as configured in
the
 > zone statement itself. And yes, the update is only forwarded
 > (successfully) once.
 >
 > BIND assumes that each zone has exactly one "primary master".
That's
 > why updates are forwarded only once. If you want a true
multi-master
 > setup, you'll need to look at other options. For example:
 >
 > - BIND with modifications or additional software.
 > - Microsoft DNS and AD-integrated zones.
 >
 > There are other options.
 >
 > Regards,
 > Chris Buxton
 > Bluecat Networks
 >
 > On 7/28/10, Gordon A. Lang  wrote:
 >> This reply is a few months delayed, but this issue is still very 
 >> important
 >> to me, and I'm hoping you can take a few minutes to help out.
 >>
 >> I finally took some time to read through the code, and
unfortunately I 
 >> was
 >> unable to identify where forward target(s) are obtained in the
update
 >> forwarding action.  There's a lot of structure to reverse
engineer -- too
 >> much for a casual effort.  So perhaps you can tell me where I can
find 
 >> the
 >> pertinent code...  ?
 >>
 >> My belief was that somewhere in the code, the SOA record is
obtained, and
 >> the MNAME is used as the forward target -- this belief was based
on trial
 >> and error observations.
 >>
 >> What you suggested is that the update forwarding actually uses
the 
 >> masters
 >> list from the named.conf file for forwarding targets.
 >>
 >> I was unable to find clues one way or another.
 >>
 >> But another thing about your response that leaves me wondering if
I fully
 >> understand your response is that you say it "walks the list of
masters
 >> trying each one in turn," and with the word "trying" in there, it

 >> suggests
 >> that it walks the list only until the first successful update. 
Perhaps I 
 >> am
 >> incorrectly reading into it, but if you could clarify that point,
I would
 >> appreciate it.  ---  I would expect that if the masters list is
used, 
 >> then
 >> ALL masters should always get the updates.
 >>
 >> Thanks in advance.
 >>
 >> --
 >> Gordon A. Lang
 >>
 >> ----- Original Message -----
 >> From: "Mark Andrews" 
 >> To: "Gordon A. Lang" 
 >> Cc: 
 >> Sent: Friday, April 09, 2010 5:58 PM
 >> Subject: Re: Bind Clustering
 >>
 >>
 >>>
 >>> In message ,
 >>> "Gordon
 >>> A. Lang" writes:
 >>>> Regarding my wild idea for synchronizing mulitiple dynamic
masters..
 >>>> my idea is flawed.
 >>>>
 >>>> Evidently, the "allow-update-forwarding" only forwards to the
MNAME
 >>>> configured in the SOA.  I was thinking it forwarded to the
masters
 >>>> configured in the conf file.  Oh well.  I guess we'll just have
to
 >>>> wait for ISC to implement multi-master replication.  Anyone
know
 >>>> when this might occur?
 >>>
 >>> What makes you say that?   If you look at the implementation it
walks
 >>> the list of masters trying each one in turn.
 >>>
 >>>> --
 >>>> Gordon A. Lang
 >>>> _______________________________________________
 >>>> bind-users mailing list
 >>>> 
 >>>> https://lists.isc.org/mailman/listinfo/bind-users
 >>> --
 >>> Mark Andrews, ISC
 >>> 1 Seymour St., Dundas Valley, NSW 2117, Australia
 >>> PHONE: +61 2 9871 4742                 INTERNET: 
 >>>
 >> _______________________________________________
 >> bind-users mailing list
 >> 
 >> https://lists.isc.org/mailman/listinfo/bind-users
 >>
 >
 > -- 
 > Sent from my mobile device
 > 
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