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Re: resolver does not re-resolve upstream servers after initial cache

November 08, 2012 06:07AM
Dave Nolan Wrote:
> >> However, this is not happening: I can watch tcpdump -n udp port 53
> but I
> >> see no re-resolution taking place.
> >>
> >> I'd love to know how to fix this. Any advice appreciated thanks!
> >
> > proxy_pass http://example.com$request_uri;
> >
> > will resolve "example.com" dynamically (assuming of course there's
> > no "upstream example.com" in configuration).
>
> Thanks very much for your help.
>
> If I switch to using example.com directly in the proxy_pass, I lose
> the
> flexibility of server groups. Is there any way of dynamically
> re-resolving servers in upstream server group?

Hi,

I can add that I lost my production servers last night because of this behavior.

* I use dynamic dns name for flexibility for almost all my servers
* I put one backend server to maintenance so the name was removed by dns (after a TTL)
* corosync manage my nginx servers... and can restart them.

You can easily understand what append :
corosync detect a problem, fail back to another server, restart nginx but nginx can't resolved a backend host in upstream so it failed to start (with "[emerg] host not found in upstream").

All my nginx servers have been down because of this.

Just like you, I can't remove my server groups but I want the flexibility of DNS resolving (Not failing at start and TTL).

--
Guilhem Lettron
Youscribe - www.youscribe.com
SubjectAuthorPosted

resolver does not re-resolve upstream servers after initial cache

Dave NolanNovember 07, 2012 03:42PM

Re: resolver does not re-resolve upstream servers after initial cache

Ruslan ErmilovNovember 08, 2012 02:36AM

Re: resolver does not re-resolve upstream servers after initial cache

Dave NolanNovember 08, 2012 05:42AM

Re: resolver does not re-resolve upstream servers after initial cache

guilhemNovember 08, 2012 06:07AM

Re: resolver does not re-resolve upstream servers after initial cache

Sergey BudnevitchNovember 08, 2012 07:06AM

Re: resolver does not re-resolve upstream servers after initial cache

Dave NolanNovember 09, 2012 04:16AM

Re: resolver does not re-resolve upstream servers after initial cache

nginxorgNovember 09, 2012 04:24AM

Re: resolver does not re-resolve upstream servers after initial cache

Sergey K.June 04, 2013 11:28AM

Re: resolver does not re-resolve upstream servers after initial cache

nginxorgNovember 09, 2012 04:26AM



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