Apache stops responding, but process is alive

Started by kenshiro, February 02, 2015, 02:36:33 PM

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kenshiro

Hi,

Apache 2.4 VC11 x64 on Win2012

I'm using apache as proxy to glassfish with simple ProxyPass.

All was OK, but recently I'm seeing an issue where apache simply stops responding. There is no error in the log files, even if I turn debug level. Process is still alive, but apache doesn't respond to requests (as it would simply "hang"). If I restart it it works for some time, then again this issue. What could cause this issue?

If I was under some Slowloris attack or if some other issue would case that connections can not be accepted any more or threads would be exhausted, wouldn't this be logged into apache log?

Has anybody ever encountered similar issue?

Thanks for help!

Gregg

Quote from: kenshiro on February 02, 2015, 02:36:33 PM
If I was under some Slowloris attack or if some other issue would case that connections can not be accepted any more or threads would be exhausted, wouldn't this be logged into apache log?

Probably not since there was no connection being established to error in the first place and you are not running out of resources which would show up.

My personal suggestion would be similar to the same Steffen gave you over at the apache lounge (but only the AcceptFilter lines), not that it's "normal" but it is "quite common".

I think there is an way to test this however, when Apache is doing this, get into the server and try connecting via http://127.0.0.1 (not localhost), if it accepts the connection then it is truly the AcceptFilter issue even if you are not seeing that error. Using the lan IP for the server from another computer on the lan may also be possible even though the server is not responding to the normal way of contacting it (via domain name).

Regardless, it's worth a try if only to confirm this is not the problem.

kenshiro

Hi,

Yesterday, before I applied those settings (as suggested by Steffen at the apache lounge) I also rebooted the server (just to make sure). After the reboot, Apache (with added settings) is rock solid. Not sure if reboot or settings helped, but I'm not in the mood to test the possible "instability" by removing the AcceptFilter lines right now, but I might try it later to see if this was really the issue.

Thanks for tips!