Merging DNS servers
Petr Špaček
pspacek at isc.org
Wed Apr 27 08:17:36 UTC 2022
On 26. 04. 22 19:47, Bob Harold wrote:
> On Tue, Apr 26, 2022 at 11:36 AM Leroy Tennison via bind-users
> <bind-users at lists.isc.org <mailto:bind-users at lists.isc.org>> wrote:
>
> I am working on shutting down a site which has an isc-bind server
> that is master for a domain and subnet which will exist elsewhere
> once the site is closed. The few remaining systems don't warrant
> such a server. My goal is to merge what remains of the
> domain/subnet into an existing server which is master for other
> domains/subnets. My current thinking is to:
>
> freeze changes on the server being retired (fortunately DHCP's DDNS
> won't be an issue by that point)
> shut down that server
> take the data files (forward and reverse zone with associated
> journal files) and place them on the remaining server
> make sure the data file types are consistent
> change the the remaining server's type from slave to master for the
> zones in question
> restart the remaining server
>
> Is this a good plan? If not, how should I proceed?
> Anything I'm missing?
>
> Thanks in advance for your input.
> --
>
> Sounds good to me. If you use "rndc freeze", then you should not need
> to copy the journal files. If there are any other secondary servers
> (and you almost always want more than just the master), then change
> those to pull from the new server, and make sure that is working, before
> starting the steps you listed.
It's almost but incomplete - first step is missing.
The very first step should be removing references to to-be-removed
server from NS set **in the parent zone** and also in the zone files you
control, and also clearing up glue records in the parent.
Then wait for (max TTL + propagation delay) computed over all RR sets
modified **in parent and child**, and only _then_ you can shutdown the
old server.
Pro tip: You can lower the TTLs before so it you do not need to wait
that long when the shutdown event is due.
Commands:
$ rndc sync -clean
$ rndc stop
... might be a good idea as well, I think.
--
Petr Špaček
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