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Questions[mpm-event](server)

Martin Hope
Soheil
Asked: 2021-12-18 01:26:57 +0800 CST
  • 1

I'm using apache MPM event on my centos server with these configs:

<IfModule event.c>
StartServers 8
ServerLimit 32
ThreadsPerChild 256
MaxRequestWorkers 8192
MaxConnectionsPerChild 10000
MinSpareThreads 125
MaxSpareThreads 250
ThreadLimit 256
KeepAlive On
KeepAliveTimeout 2
MaxKeepAliveRequests 500
</IfModule>

now what I need is to check what number of servers and threads are currently created by apache. how can I check these values?

linux centos apache-2.4 mpm-event
Martin Hope
Michal Černý
Asked: 2020-11-04 07:31:24 +0800 CST
  • 3

I did update on server to php7.3-fpm to get http2 working. Setup everything needed, h2 works great, all websites is up. But like every 5 minutes server get stuck on these errors until I restart apache.

I checked all configs, tried to calculate MaxRequestWorkers, maxclients, pm.max_children, pm.start_servers, pm.min_spare_servers, pm.max_spare_servers. Every change make it worse or make it stay longer.

Server config

  • debian 10
  • apache 2.4.38
  • php 7.3.14
  • 5.8GB memory
  • 2 x Intel(R) Xeon(R) CPU E3-1585L v5 @ 3.00GHz

Server stats

Errors

[Tue Nov 03 15:30:07.450356 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 31148 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:07.450391 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 31149 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:07.450397 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5692 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:07.450401 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5860 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:07.450406 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5982 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:07.450410 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 6138 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:09.452520 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 31148 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:09.452556 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 31149 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:09.452562 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5692 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:09.452567 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5860 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:09.452573 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5982 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:09.452578 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 6138 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:11.454710 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 31148 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:11.454739 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 31149 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:11.454744 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5692 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:11.454760 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5860 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:11.454764 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 5982 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:11.454768 2020] [core:warn] [pid 31147:tid 139885881660544] AH00045: child process 6138 still did not exit, sending a SIGTERM
[Tue Nov 03 15:30:13.456926 2020] [core:error] [pid 31147:tid 139885881660544] AH00046: child process 31148 still did not exit, sending a SIGKILL
[Tue Nov 03 15:30:13.456983 2020] [core:error] [pid 31147:tid 139885881660544] AH00046: child process 31149 still did not exit, sending a SIGKILL
[Tue Nov 03 15:30:13.457006 2020] [core:error] [pid 31147:tid 139885881660544] AH00046: child process 5692 still did not exit, sending a SIGKILL
[Tue Nov 03 15:30:13.457028 2020] [core:error] [pid 31147:tid 139885881660544] AH00046: child process 5860 still did not exit, sending a SIGKILL
[Tue Nov 03 15:30:13.457059 2020] [core:error] [pid 31147:tid 139885881660544] AH00046: child process 5982 still did not exit, sending a SIGKILL
[Tue Nov 03 15:30:13.457094 2020] [core:error] [pid 31147:tid 139885881660544] AH00046: child process 6138 still did not exit, sending a SIGKILL
[Tue Nov 03 15:30:14.458349 2020] [mpm_event:notice] [pid 31147:tid 139885881660544] AH00491: caught SIGTERM, shutting down

Server mpm-event.conf

<IfModule mpm_event_module>
    StartServers             2
    MinSpareThreads      25
    MaxSpareThreads      75
    ThreadLimit          64
    ThreadsPerChild      25
    MaxRequestWorkers     150
    MaxConnectionsPerChild   0
</IfModule>

Thanks for support,

debian php-fpm apache-2.4 mpm-event
Martin Hope
James Connigan
Asked: 2020-04-17 08:13:59 +0800 CST
  • 1

I am googling around and finding myself going down a rabbit hole and getting nowhere.

My over all goal is to limit the number of connections that can be made at the same time to Apache on a Centos 7 server.

With the default setting:

[root@app1 ~]# cat /etc/httpd/conf.modules.d/00-mpm.conf
LoadModule mpm_prefork_module modules/mod_mpm_prefork.so
#LoadModule mpm_worker_module modules/mod_mpm_worker.so
#LoadModule mpm_event_module modules/mod_mpm_event.so

[root@app1 ~]# httpd -t -D DUMP_MODULES | grep mpm
 mpm_prefork_module (shared)

[root@app1 ~]# httpd -V | grep MPM
Server MPM:     prefork

If I run:

[root@app1 ~]# ab -n 200 -c 100 http://afterratest.com/

I can see about 135 connections coming in.

If i set the following setting in the httpd.conf file

KeepAlive Off
<IfModule prefork.c>
   StartServers        5
   MinSpareServers     5
   MaxSpareServers     100
   MaxClients          100
   MaxRequestsPerChild 3000
</IfModule>

Restart Apache and run the same command I can see 100 connections.

What I am hoping to get form this question is:

  1. What is the difference between mpm_prefork_module, mpm_worker_module and mpm_event_module

I have read the docs online and they do not make sense.

  1. What do the following setting do for each?

    StartServers 5

    MinSpareServers 5

    MaxSpareServers 100

    MaxClients 100

    MaxRequestsPerChild 3000

Explain it like I am 5

apache-2.4 mpm-worker centos7 mpm-event mpm-prefork
Martin Hope
TheMonkeyKing
Asked: 2020-03-20 04:15:23 +0800 CST
  • 1

My Apache with ModSecurity, mod_evasive20 enabled occasionally geting crashed:

These are glimpse of error log:

[core:warn]**: child process 24709 still did not exit, sending a SIGTERM
[core:error]**: child process 24709 still did not exit, sending a SIGKILL
[mpm_event:notice] **: caught SIGTERM, shutting down

Last time Apache a crashed when google analytic reported 2K+ live views. I see too many child process can also be a result of attack like DDoS. But I want to make sure is that really an attack or a configuration flaw.

Please help.

Machine: Ubuntu 18.04, 16 GB RAM, 8 Core CPU, 180GB SSD

MPM Event Configuration:

<IfModule mpm_event_module>
    StartServers         2
    MinSpareThreads      25
    MaxSpareThreads      150
    ThreadLimit      250
    ThreadsPerChild      250
    MaxRequestWorkers    6250
    ServerLimit      25
    MaxConnectionsPerChild   0
</IfModule>

Detailed Error Log:

[Thu Mar 19 06:25:02.506142 2020] [mpm_event:notice] [pid 1460:tid 139655311739840] AH00489: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.0g Apache configured -- resuming normal operations
[Thu Mar 19 06:25:02.506172 2020] [core:notice] [pid 1460:tid 139655311739840] AH00094: Command line: '/usr/sbin/apache2'
[Thu Mar 19 09:15:42.817591 2020] [core:warn] [pid 1460:tid 139655311739840] AH00045: child process 24709 still did not exit, sending a SIGTERM
[Thu Mar 19 09:15:44.819958 2020] [core:warn] [pid 1460:tid 139655311739840] AH00045: child process 24709 still did not exit, sending a SIGTERM
[Thu Mar 19 09:15:46.822259 2020] [core:warn] [pid 1460:tid 139655311739840] AH00045: child process 24709 still did not exit, sending a SIGTERM
[Thu Mar 19 09:15:48.824514 2020] [core:error] [pid 1460:tid 139655311739840] AH00046: child process 24709 still did not exit, sending a SIGKILL
[Thu Mar 19 09:15:49.826497 2020] [mpm_event:notice] [pid 1460:tid 139655311739840] AH00491: caught SIGTERM, shutting down
[Thu Mar 19 09:15:49.962067 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity for Apache/2.9.2 (http://www.modsecurity.org/) configured.
[Thu Mar 19 09:15:49.962131 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity: APR compiled version="1.6.2"; loaded version="1.6.3"
[Thu Mar 19 09:15:49.962136 2020] [:warn] [pid 29976:tid 140194146679744] ModSecurity: Loaded APR do not match with compiled!
[Thu Mar 19 09:15:49.962140 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity: PCRE compiled version="8.39 "; loaded version="8.39 2016-06-14"
[Thu Mar 19 09:15:49.962144 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity: LUA compiled version="Lua 5.1"
[Thu Mar 19 09:15:49.962147 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity: YAJL compiled version="2.1.0"
[Thu Mar 19 09:15:49.962150 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity: LIBXML compiled version="2.9.4"
[Thu Mar 19 09:15:49.962154 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity: Original server signature: Apache/2.4.29 (Ubuntu)
[Thu Mar 19 09:15:49.962157 2020] [:notice] [pid 29976:tid 140194146679744] ModSecurity: Status engine is currently disabled, enable it by set SecStatusEngine to On.
[Thu Mar 19 09:15:50.025004 2020] [mpm_event:notice] [pid 29986:tid 140194146679744] AH00489: Apache/2.4.29 (Ubuntu) OpenSSL/1.1.0g Apache configured -- resuming normal operations
[Thu Mar 19 09:15:50.025066 2020] [core:notice] [pid 29986:tid 140194146679744] AH00094: Command line: '/usr/sbin/apache2'

If any additional info need, please mention. Thanks.

php ddos apache2 mod-security mpm-event
Martin Hope
user43403
Asked: 2010-05-18 16:38:49 +0800 CST
  • 6

I have recently upgraded my Apache2 server, and am now unable to run a CGI app. My logs are showing

(13) Permission denied unable to connect to cgi deamon after multiple tries

I understand that the error message means Apache is being denied some permission to some file, and I'm stumped as to how to track down and solve the problem.

Is the file mentioned in the error message truly the blocked file? Or might the problem be caused by some other needed file? The .cgi file is right where it has always been, under /usr/share. The file ownership (root) and permissions (world readable/executable) are the same as they have always been for the file and its ancestors. The SELinux file labels are unchanged.

The SELinux audit log shows no denial associated with Apache nor the CGI program. In case of a donotaudit condition, I enabled audit, but still saw nothing. I switched SELinux into permissive mode briefly, to no avail. I even tried restarting Apache while in permissive mode. This did not solve the problem.

Any suggestions on how to solve this problem? I'm tempted to just revert to the older Apache.

apache-2.2 apache-2.4 selinux mpm-event