Re: [DNSOP] New Version Notification for draft-pusateri-dnsop-update-timeout-00.txt

[Tom Pusateri <[e-mail]>]

> On Aug 25, 2018, at 2:53 PM, Paul Vixie <[e-mail]> wrote:
> 
> On Saturday, August 25, 2018 6:11:48 PM UTC Tom Pusateri wrote:
>> ...
>> 
>> In most cases, having the primary remember the lease lifetime should be
>> enough. But if the outage is longer than the lease lifetime, it would
>> better if the secondary would also have that information.
> 
> you seem to be proposing that the "secondary" servers, by which i mean those 
> not the primary master, alter the zone contents in a way that's visible to 
> query initiators, independently. if so, i oppose this, in the form proposed.
> 
> to have more than one source of DNS truth requires "multi-master", so that 
> zone identity can be partitioned and healed, following partitions and healings 
> of the connectivity of each responder and its cloud of reachable clients. one 
> of the hard problems here is split horizon. another is incompatible deltas at 
> heal time. the database world has grappled with this topic, having varying 
> degrees of success, for as long as there have been computer networks.
> 
> i would like to see DNS add "multi-master". several proprietary vendor 
> extensions do various parts of this -- though none of them that i know of can 
> handle split horizon or incompatible deltas. and tellingly, none has been 
> opened to the community in the form of a standardization effort.
> 
> if on the other hand you only intend to carry the timeout information as zone 
> data transferred in AXFR/IXFR in case a sysop decides that the primary master 
> will be offline indefinitely and wants to manually promote one of the 
> "secondary" servers to the role of primary master, then i have no objection. 
> that's why the TUU and TUD RR's of my 1996 "defupd" proposal are in-zone data 
> rather than stored in some ancillary location reachable only by the primary 
> master.
> 
> can you verify that you do not intend secondary servers to automatically 
> expire records, independent of hearing IXFR/AXFR updates from the primary 
> master, after the primary master applies its own copy of your TIMEOUT RR's?
> 
> -- 
> Vixie
> 

I agree that the secondary servers should not expire records. In the case of promotion, I also agree that this sounds like a good strategy.

Thanks for pointing out this distinction.

Tom