[Pdns-users] powerdns authoritative 4.0.0 alpha stops working from time to time

Alejandro Adroher Mellado alejandro.adroher at omniaccess.com
Fri Nov 11 10:15:10 UTC 2016


Hi Oliver, 

I have been researching on my database schema and all the changes required for version 3.4 (it's mean, compatible with 4.0 version) were already implemented in the database previously, so all my name server databases are also compatible with Authoritative services 4.0.

So, the version is not the problem.
I still having enabled the loging options ready for if the error happen again.

Alejandro

-----Original Message-----
From: Oliver Peter [mailto:lists at peter.de.com] 
Sent: viernes, 11 de noviembre de 2016 10:43
To: Alejandro Adroher Mellado <alejandro.adroher at omniaccess.com>
Cc: pdns-users at mailman.powerdns.com
Subject: Re: [Pdns-users] powerdns authoritative 4.0.0 alpha stops working from time to time

On Fri, Nov 11, 2016 at 09:33:30AM +0000, Alejandro Adroher Mellado wrote:
> Hi Oliver,
> 
> You are right, I did not because as is happening also on version 4.0.0, It had nothing to do with the local configuration and yes with the application code. 
> 
> My database is really small. The server has almost no load.
> Authoritative has been Upgraded: pdns-server:amd64 (3.3-2ubuntu0.1, 
> 4.0.1-1pdns.trusty) The database is a replica from a pdns-server 
> 3.3-2ubuntu0.1 (My master server) Maybe my problem is the versioning between my pdns-server 4 having a DB Replica coming from 3.3-2 database.
> 
> I updated to 4 version this server because is a new one, it has been sent far from the main office and also because the last "PowerDNS Security Advisory 2016-01".
> 
> Here we have the most relevant configuration I have set.
> ## Ubuntu 14.04 - amd64
> dnsdist                                    1.1.0~beta1-1pdns.trusty
> pdns-backend-mysql        4.0.1-1pdns.trusty
> pdns-recursor                      3.7.3-1
> pdns-server                          4.0.1-1pdns.trusty
> 
> ## Pdns.conf
> chroot=./
>  config-dir=/etc/powerdns
> daemon=yes
>  guardian=yes
> include-dir=/etc/powerdns/pdns.d
> local-port=53
> loglevel=7
> module-dir=/usr/local/lib/pdns
> out-of-zone-additional-processing=no
> query-logging=yes
> socket-dir=/var/run
> 
> ## pdns.local.gmysql.conf
> gmysql-host=127.0.0.1
> gmysql-port=3306
> gmysql-dbname=pdns
> 
> 
> So, from my point of view must be the version on the replica master-->slave, but I'm not sure.

If I get this right you are replicating from a MySQL database which is still the schema from 3.3 but your server is 4.0.1.  This might lead to some problems, look at the changes here:
	https://doc.powerdns.com/3/authoritative/upgrading/

Since your database is on localhost you could also try connecting to the unix socket instead of TCP on port 3306, e.g.:
	gmysql-socket=/var/lib/mysql/mysql.sock

(caution, might cause problems with your chroot option)


> Anyone has something to add?
> 
> Thanks a lot,
> Alejandro.
> 
> 
> 
> -----Original Message-----
> From: Oliver Peter [mailto:lists at peter.de.com]
> Sent: jueves, 10 de noviembre de 2016 15:37
> To: Alejandro Adroher Mellado <alejandro.adroher at omniaccess.com>
> Cc: pdns-users at mailman.powerdns.com
> Subject: Re: [Pdns-users] powerdns authoritative 4.0.0 alpha stops 
> working from time to time
> 
> Hi Alejandro,
> 
> On Thu, Nov 10, 2016 at 10:48:18AM +0000, Alejandro Adroher Mellado wrote:
> > Morning!! 
> > 
> > I'm having the same issue with Authoritative 4.0.1-1pdns.trusty.
> > 
> > In my case, there is no a SERVFAIL response.
> > 
> > Backend reported permanent error which prevented lookup (GSQLBackend 
> > lookup query:Could not execute mysql statement: SELECT 
> > content,ttl,prio,type,domain_id,disabled,name,auth FROM records 
> > WHERE
> > disabled=0 and type=? and name=?: Lost connection to MySQL server 
> > during query), aborting
> > 
> > I'm also added to may config the loglevel=7 and the query-logging=yes so I will wait for the Warning message again.
> 
> The people here probably need some more information about your setup;  pdns.conf, my.cnf / Information about Operating system etc would be very helpful.
> Furthermore information about the workload would be nice, too (size of your database, queries per second, etc).
> Is it a fresh setup or did you upgrade from a previous powerdns / centos / mysql version?
> 
> 	
> Cheers
> Oliver
> 
> 
> > 
> > Kind Regards,
> > Ale.
> > 
> > 
> > -----Original Message-----
> > From: Pdns-users [mailto:pdns-users-bounces at mailman.powerdns.com] On 
> > Behalf Of Radoslaw Piliszek
> > Sent: lunes, 7 de marzo de 2016 13:49
> > To: pdns-users at mailman.powerdns.com
> > Subject: Re: [Pdns-users] powerdns authoritative 4.0.0 alpha stops 
> > working from time to time
> > 
> > Hello,
> > 
> > I am having the same problem using PowerDNS Authoritative Server
> > 4.0.0-alpha2 from CentOS 7 repository and the MySQL backend.
> > 
> > I enabled the highest level of logging (9).
> > 
> > And here are the results...
> > 
> > First failed queries (e.g. three times for three connections to the backend):
> > 
> > Remote 127.0.0.1 wants '...', do = 0, bufsize = 512: packetcache 
> > MISS
> > Query: SELECT content,ttl,prio,type,domain_id,disabled,name,auth FROM records WHERE disabled=0 and type=? and name=?
> > Backend reported condition which prevented lookup (GSQLBackend 
> > lookup
> > query: Could not execute mysql statement: SELECT 
> > content,ttl,prio,type,domain_id,disabled,name,auth FROM records 
> > WHERE
> > disabled=0 and type=? and name=?: Lost connection to MySQL server 
> > during query) sending out servfail
> > 
> > All following queries:
> > 
> > Remote 127.0.0.1 wants '...', do = 0, bufsize = 512: packetcache 
> > MISS Backend reported condition which prevented lookup (GSQLBackend 
> > lookup
> > query: Attempt to bind more parameters than query has: SELECT 
> > content,ttl,prio,type,domain_id,disabled,name,auth FROM records 
> > WHERE
> > disabled=0 and type=? and name=?) sending out servfail
> > 
> > There are no other log messages in between these.
> > 
> > After the connection is lost, the "Attempt to bind more parameters than query has" (as already mentioned here) appears until the PowerDNS server is restarted...
> > 
> > Also, in my setup the connection is lost due to timeout because in this test environment queries appear very rarely. I think PowerDNS should handle timeouted sessions more gracefully like trying to restart the connection instead of failing the DNS request...
> > 
> > In summary, two problems:
> > 1) Connection to backend lost = queries stuck on error.
> > 2) Session timeouts are not handled gracefully.
> > 
> > C
> > Radosław Piliszek
> > 
> > > On 26 Feb 2016, at 15:18, Pieter Lexis <pieter.lexis at powerdns.com> wrote:
> > >
> > > Hi Peter,
> > >
> > > On Fri, 26 Feb 2016 14:49:16 +0200 Keresztes Péter-Zoltán <zozo at 
> > > z0z0.tk> wrote:
> > >
> > >> I have installed the new 4.0 version of the pdns. It works great however from time to time it suddenly stops working. In the logs I see lots of these:
> > >
> > > By "stops working", do you mean that the process dies or it just stops responding or it only sends out SERVFAILs?
> > >
> > >> Feb 26 07:42:34 dns1 pdns[6514]: Backend reported condition which 
> > >> prevented lookup (GSQLBackend lookup query: Attempt to bind more 
> > >> parameters than query has: SELECT 
> > >> content,ttl,prio,type,domain_id,disabled,name,auth FROM records 
> > >> WHERE
> > >> disabled=0 and type=? and name=?) sending out servfail
> > >
> > > This is the `basic-query`, interesting that it gives this error, as we never bind more than 2 elements in the code.
> > >
> > > If your server is not stressed for resources could you set `query-logging=yes` in the pdns.conf (with possibly `loglevel=7` as well if no queries show up in syslog) to identify the query that causes this and share the results with us?
> > >
> > > Secondly, could you share your pdns.conf (without passwords)?
> > >
> > > Best regards,
> > >
> > > Pieter
> > >
> > > --
> > > Pieter Lexis
> > > PowerDNS.COM BV -- https://www.powerdns.com 
> > > _______________________________________________
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> > > Pdns-users at mailman.powerdns.com 
> > > http://mailman.powerdns.com/mailman/listinfo/pdns-users
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> 
> -- 
> Oliver PETER       oliver at gfuzz.de       0x456D688F

-- 
Oliver PETER       oliver at gfuzz.de       0x456D688F


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