Is it possible to monitor the fair proxy balancer?
grzegorz.nosek at gmail.com
Sat Jun 28 15:51:02 MSD 2008
On sob, cze 28, 2008 at 02:23:02 +0200, Robbie Allen wrote:
> Periodically one or more of my mongrel instances will stop getting
> requests from nginx (via upstream fair). The mongrel process is still
> running, but not getting any requests.
The standard question: are you running the latest snapshot? (there was
an update about a week ago). If not, please give it a try.
I guess I should start versioning the module ;)
> How can I verify if nginx has taken it out of service? Is it possible
> to get details on the current status of the fair proxy?
No, not really. This is something I'd like to do but currently there's
no support for pluggable status reports and I think that writing what
would effectively become another module for monitoring upstream_fair is
--with-debug and debug_http may help but you'd probably drown in the
massive amount of logs (not only from upstream_fair, nginx itself is
very chatty too).
> I also see the following error in syslog, but I'm unsure if it is
> nginx: segfault at 00007fffa0869fd0 rip 00002ac509ea61e3 rsp
> 00007fffa0869ed0 error 6
That one looks strange. It's a segfault while accessing the stack
*above* the stack pointer, which should be legal, unless something has
just allocated at least 304 bytes of stack space and overflowed it.
I can't see any large stack allocations in upstream_fair (though I may
have overlooked something), so it may come from nginx itself as well.
Please try increasing the stack size (ulimit -s <something> in your
nginx startup script).
If such a segfault repeats (or if you haven't restarted nginx since
then; reloads are fine), please collect:
- result of pmap pid-of-any-nginx-worker (they should have the same
memory map), alternatively cat /proc/<pid>/maps
- the log line with the faulting address, rip and rsp (like above)
- your nginx binary
The above information should prove helpful while tracing the cause of
More information about the nginx