12-09-2019 06:15 PM
Is there a way to update (delete/create) an arecord to convert it to a cname without the possibility of a nxdomain response that will get negatively cached?
Hope this makes sense.
12-10-2019 04:19 AM
Hmmm, interesting one, because changes are dynamically applied, so there will always be a gap between when the A record is deleted and the CNAME is created. I assume you are trying to minimise this gap because you have a constant stream of queries for that name?
All I can think of at the moment is to reduce the negative cache timer of the zone to 0 or maybe 1 second if 0 doesn't work, then delete your A record, add the CNAME and then increase it again afterwards. If you do reduce the negative cache TTL you'll probably have to wait for zone TTL to expire before you do any changes else other resolvers out there might still have the old negative cache TTL cached.
12-10-2019 05:44 AM
You are correct; constant lookups and we were hoping to eliminate all the NXDOMAINS. We were thinking about lowering the negative cache, as well, but there are some concerns from our tech guys performing this against the entire domain.
Would there be a way to export the config, update it manually and reload it? Though, that may sound worse than lowering the cache.
12-10-2019 06:23 AM
I don't know a way to export and reload the zone without a lot of disruption. The CSV export/import manager will be too slow. You almost need a way to disable the dynamic update so that you can pre-stage the changes then do a restart services to load them together. I don't know if there's a way to stop the UI from dynamically updating the zone.
You could maybe try using the CLI, there's a ddns_delete and ddns_add comand you might be able to use in quick succession - more details here:
12-10-2019 06:24 AM
The other option is to use the API to quickly delete and add the records in succession, should only take fractions of a second.