Re: Help: Apache Crashing Everyday (Apache Users)

Hi!

2017-04-19 8:41 GMT+02:00 Jayaram Ponnusamy <jayaram.ponnusamy@xxxxxxxxx>:

Hi Luca,

Thanks for the details.
1. our server's ulimit values are:
]$ ulimit -a
max user processes (-u) 1024

Please let me know whether the values are sufficient to allow at least 500 concurrent connections.

To be sure you should check /proc/$pid/limits (where $pid is one of the Apache processes), but I'd say that your original issue (quoting "and when the Total Children value is reached 999 the Apache is not responding") is related to this limit being enforced.

2. Yes I checked mod_jk log when hang happens, and getting below errors continuously.

[Wed Apr 19 02:00:38 2017]loadbalancer www.cmsp1.com 24.843284
[Wed Apr 19 02:00:38 2017][16313:3878614784] [info] ajp_process_callback::jk_ajp_common.c (1788): Writing to client aborted or client network problems
[Wed Apr 19 02:00:38 2017][16313:3878614784] [info] ajp_service::jk_ajp_common.c (2447): (qu_prod_live_svr1) sending request to tomcat failed (unrecoverable), because of client write error (attempt=1)
[Wed Apr 19 02:00:38 2017][16313:3878614784] [info] service::jk_lb_worker.c (1384): service failed, worker qu_prod_live_svr1 is in local error state
[Wed Apr 19 02:00:38 2017][16313:3878614784] [info] service::jk_lb_worker.c (1403): unrecoverable error 200, request failed. Client failed in the middle of request, we can't recover to another instance.
[Wed Apr 19 02:00:38 2017]loadbalancer www.cmsp1.com 19.170901
[Wed Apr 19 02:00:38 2017][16313:3878614784] [info] jk_handler::mod_jk.c (2608): Aborting connection for worker=loadbalancer
[Wed Apr 19 02:00:39 2017][16261:3878614784] [warn] map_uri_to_worker_ext::jk_uri_worker_map.c (962): Uri * is invalid. Uri must start with /
[Wed Apr 19 02:00:40 2017][16308:3878614784] [warn] map_uri_to_worker_ext::jk_uri_worker_map.c (962): Uri * is invalid. Uri must start with /

Was apache asked to reload for logrotation before this? Or did you see an increase in traffic?

3. We will upgrade to 2.4.25, could you please share optimal configuration for mpm-event to allow more concurrent users, please.

I'd suggest to start from https://httpd.apache.org/docs/2.4/mod/event.html, but every server has its own set of requirements and a proper configuration needs a bit of testing, so I suggest to set up a fake production environment first and start playing with 2.4.25 in there first.

Please also check https://httpd.apache.org/docs/current/upgrading.html, upgrading to 2.4 is not super difficult but you'll might be required to make some changes to your config.

Hope that helps!

Luca