[Pdns-users] pipe backend + slave + bad zones = bug

[crayon at leechbox.net]

crayon at leechbox.net wrote:
> Hi,
>
> I have a slave PowerDNS server which uses a pipe and gmysql backend. 
> Two of the zones on the master have out of zone-data that PowerDNS 
> (rightfully) does not like. Whenever PowerDNS tries to AXFR those 
> domains, it also launches a co-process, which then hangs.
>
> I tried this with the sample perl script here: 
> http://doc.powerdns.com/backends-detail.html#PIPEBACKEND  to make sure 
> it wasn't my co-process.
>
> My syslog looks like this:
>
> Oct 29 15:47:32 c1ns2 pdns[16140]: 2 slave domains need checking
> Oct 29 15:47:32 c1ns2 pdns[16140]: Domain xxx is stale, master serial 
> 46, our serial 0
> Oct 29 15:47:32 c1ns2 pdns[16140]: Domain yyy is stale, master serial 
> 128, our serial 0
> Oct 29 15:47:32 c1ns2 pdns[16140]: Backend launched with banner: 
> OK#011Sample backend firing up
> Oct 29 15:47:32 c1ns2 pdns[16140]: gmysql Connection succesful
> Oct 29 15:47:32 c1ns2 pdns[16140]: AXFR started for 'xxx', transaction 
> started
> Oct 29 15:47:32 c1ns2 pdns[16140]: Remote 10.9.10.1 sneaked in 
> out-of-zone data 'ns1.example.com' during AXFR of zone 'xxx'
> Oct 29 15:47:32 c1ns2 pdns[16140]: Backend launched with banner: 
> OK#011Sample backend firing up
> Oct 29 15:47:32 c1ns2 pdns[16140]: gmysql Connection succesful
> Oct 29 15:47:32 c1ns2 pdns[16140]: AXFR started for 'yyy', transaction 
> started
> Oct 29 15:47:32 c1ns2 pdns[16140]: Remote 10.9.10.1 sneaked in 
> out-of-zone data 'ns1.example.com' during AXFR of zone 'yyy'
>
> After that I have two defunct co-processes that I need to restart 
> PowerDNS to get rid of. Eventually it will run out of file descriptors 
> and give another error.
>
> Obviously I should fix my zones, but this is bad behavior of PowerDNS 
> as well.
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If anyone else runs into this, I found the bug is fixed in the 
pipebackend SVN revision 1064 
<http://wiki.powerdns.com/cgi-bin/trac.fcgi/changeset/1064>.

Maybe also notable, the slave functionality in current SVN handles AXFR 
out-of-zone data differently, ignoring bad records instead of skipping 
the whole zone.

For now I'll use the SVN pipebackend and eagerly wait for the next 
official PowerDNS release :>