DNS caching issue

Andrew Alexeev andrew at nginx.com
Wed Nov 16 08:23:45 UTC 2011


On Nov 16, 2011, at 1:58 AM, James Lyons wrote:

> So we are using nginx from a few builds back as upgrading consistently
> has proven difficult for our ops team to keep up with where I work.  I
> think we're on 1.0.5.
> We have some hosts setup to handle subrequests using proxy_pass
> directive.  When the DNS record is changed, and the host command on
> the machine is reporting a *new* host ip in the dns result.  That host
> does not see traffic like it should.
> We have always attributed this to caching in dns and we perform "nginx
> reconfigure" to reparse conf and re-read dns.  This isn't working for
> us though and i'm not sure why.  We did upgrade to 1.0.5 relatively
> recently and i'm wondering if we inherited a bug.  Two things are odd
> though.
> When we pulled the host ip *out* of the dns, and performed nginx
> reconfigure, the traffic to the machine ceased.  But now that our work
> is done, and we're trying to put it back into rotation, nginx
> reconfigure does not seem to be working.
> Doing a restart is harder, as we have to drain the machine in
> question.  But is there any known behavior that might be the root
> cause of this?  Far as I'm aware the TTL on the DNS is 5m.  But its
> been hours since the change.

Can you please show the relevant portion of your proxy configuration?

> -James-
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