receiving 502 bad gateway when I browse zabbix frontend.

[Qian]

Hello Members,

I have a problem. Recently, I always receive 502 bad gateway after httpd ran few days.

To fix this issue, I need to restart httpd service. this issue becomes more and more frequency this week.

I found a strange thing. The issue happens when the connection httpd reach "258" *(ps aux }grep httpd |wc -l). I have increased max connection number of httpd on httpd.conf file. It is not help.

Do you have any idea to solidly fix this issue?

zabbix server hardware:
system t3.large
/0 bus Motherboard
/0/0 memory 64KiB BIOS
/0/4 processor Intel(R) Xeon(R) Platinum 8259CL CPU @ 2.50GHz
/0/1 memory 8GiB System memory
/0/100 bridge 440FX - 82441FX PMC [Natoma]
/0/100/1 bridge 82371SB PIIX3 ISA [Natoma/Triton II]
/0/100/1.3 generic 82371AB/EB/MB PIIX4 ACPI
/0/100/3 display Amazon.com, Inc.
/0/100/4 storage Amazon.com, Inc.
OS: centos 7
database is deployed in separate server.


Thanks in advance.

[Qian]

i have checked error_log on /var/log/httpd/

[Sat Mar 21 06:55:33.344302 2020] [proxy:debug] [pid 12744] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:55:33.344328 2020] [proxy:debug] [pid 12744] proxy_util.c(1936): AH00931: initialized single connection worker in child 12744 for (*)
[Sat Mar 21 06:57:06.456677 2020] [proxy:debug] [pid 12844] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:57:06.456731 2020] [proxy:debug] [pid 12844] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:57:06.456767 2020] [proxy:debug] [pid 12844] proxy_util.c(1936): AH00931: initialized single connection worker in child 12844 for (*)
[Sat Mar 21 06:57:09.462105 2020] [proxy:debug] [pid 12850] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:57:09.462148 2020] [proxy:debug] [pid 12850] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:57:09.462175 2020] [proxy:debug] [pid 12850] proxy_util.c(1936): AH00931: initialized single connection worker in child 12850 for (*)
[Sat Mar 21 06:57:12.467052 2020] [proxy:debug] [pid 12853] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:57:12.467093 2020] [proxy:debug] [pid 12853] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:57:12.467119 2020] [proxy:debug] [pid 12853] proxy_util.c(1936): AH00931: initialized single connection worker in child 12853 for (*)
[Sat Mar 21 06:57:13.470780 2020] [proxy:debug] [pid 12855] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:57:13.470830 2020] [proxy:debug] [pid 12855] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:57:13.470861 2020] [proxy:debug] [pid 12855] proxy_util.c(1936): AH00931: initialized single connection worker in child 12855 for (*)
[Sat Mar 21 06:57:13.472857 2020] [proxy:debug] [pid 12856] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:57:13.472891 2020] [proxy:debug] [pid 12856] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:57:13.472913 2020] [proxy:debug] [pid 12856] proxy_util.c(1936): AH00931: initialized single connection worker in child 12856 for (*)
[Sat Mar 21 06:58:08.540398 2020] [proxy:debug] [pid 12924] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:58:08.540454 2020] [proxy:debug] [pid 12924] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:58:08.540488 2020] [proxy:debug] [pid 12924] proxy_util.c(1936): AH00931: initialized single connection worker in child 12924 for (*)
[Sat Mar 21 06:58:15.550782 2020] [proxy:debug] [pid 12931] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:58:15.550826 2020] [proxy:debug] [pid 12931] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:58:15.550852 2020] [proxy:debug] [pid 12931] proxy_util.c(1936): AH00931: initialized single connection worker in child 12931 for (*)
[Sat Mar 21 06:58:54.597878 2020] [proxy:debug] [pid 12979] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:58:54.597931 2020] [proxy:debug] [pid 12979] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local
[Sat Mar 21 06:58:54.597966 2020] [proxy:debug] [pid 12979] proxy_util.c(1936): AH00931: initialized single connection worker in child 12979 for (*)
[Sat Mar 21 06:59:15.621899 2020] [proxy:debug] [pid 13003] proxy_util.c(1843): AH00925: initializing worker proxy:reverse shared
[Sat Mar 21 06:59:15.621943 2020] [proxy:debug] [pid 13003] proxy_util.c(1885): AH00927: initializing worker proxy:reverse local

[Hamardaban]

Your problem is related to configuring the apache web server, not zabbix. I recommend that you find out what Apache modules you have installed and how they interact (for example, mod_proxy).

[Qian]

Hello Hamardaban,

Thanks for your replied.

I have installed below modules:

proxy_module (shared)
proxy_ajp_module (shared)
proxy_balancer_module (shared)
proxy_connect_module (shared)
proxy_express_module (shared)
proxy_fcgi_module (shared)
proxy_fdpass_module (shared)
proxy_ftp_module (shared)
proxy_http_module (shared)
proxy_scgi_module (shared)
proxy_wstunnel_module (shared)

Sorry, I am not familiar with Apache? I have tried to do some investigation for Apache, but still not able to fix this issue. I would really appreciate if you can guide me more detail. Thanks in advance.