Want to subscribe to topics you're interested in?
Become a Member

502 Errors Nginx Vbulletin

Discussion in 'Nginx, PHP-FPM & MariaDB MySQL' started by Mayank, Sep 9, 2015.

Tags:
  1. Mayank

    Mayank New Member

    7
    2
    3
    Sep 8, 2015
    India
    Ratings:
    +2
    Local Time:
    12:15 PM
    1.9
    10.0.21
    Hi there,

    I just moved my forum from other server (same cloud VPS, same config) to new server where I'm using CentminMod with CentOS 7. I have shifted after 5 years, so I don't remember if I had similar errors and how I fixed.

    My Vbulletin forum (V3.8) is giving massive 502 errors, not much while browsing but /Admincp is a mess. Every page I browse gives 502 errors mostly.

    This site had VBSEO rewrite rules, now I've added rewrite rules to move VBSEO urls back to normal VB urls.

    Do I have to change some Nginx or php settings that may stop these errors? Some years back these errors came and I fixed somehow. But not sure what to do now. I am moving soon from VB to Burning Board, but I'd like to fix this issue so it doesn't happen on new forum post conversion.

    502errors.png

    A few things I had done while conversion was I shut off Zend Opcache from php-fpm file. I increased memory_limit from 160 to 512M.

    Any idea on how to fix this 502 mess?

    Thanks,
    Mayank
     
  2. eva2000

    eva2000 Administrator Staff Member

    28,943
    6,570
    113
    May 24, 2014
    Brisbane, Australia
    Ratings:
    +9,751
    Local Time:
    4:45 PM
    Nginx 1.13.x
    MariaDB 5.5
    Zend Opcache improves PHP performance so disabling it isn't recommended

    Centmin Mod is provide as is, so short of scripted related bugs or issues, any further optimisation to the web stack components - nginx, php-fpm, mariadb mysql, csf firewall etc or web app specific configurations are left to the Centmin Mod user to deal with. So I do not provide any free support for such.

    Nginx 502 or 504 Bad Gateway Errors



    Bad gateway 502 /504 timeouts are usually related to Nginx timing out waiting on PHP-FPM to respond as PHP-FPM is overloaded or overwhelmed with requests, so may need to tune PHP-FPM values. It also maybe due to PHP-FPM in turn being queued and backed up waiting on MariaDB MySQL server to respond - so also need to look at MySQL.

    You'll need to tune your PHP-FPM settings and this is left up to end user to do but here's a thread for starters to enable php status page output outlined at PHP-FPM - CentminMod.com LEMP Nginx web stack for CentOS and PHP-FPM - pm.max_children | Centmin Mod Community which outlines the official PHP-FPM config documentation as well.

    Checking PHP-FPM etc logs



    You'll also need to check into your PHP-FPM, Nginx and MariaDB logs which you can find as outlined at How to troubleshoot Centmin Mod initial install issues

    Server logs include Nginx, PHP-FPM, MariaDB MySQL error logs as well as others. You can find your Centmin Mod install/menu logs at FAQ 7 and server logs at FAQ 19 at Centmin Mod FAQ (most up to date info in FAQ so always read that first). Spoiler tag below has info too but may not be up to date.

    Some of Centmin Mod's installed software will have their own access and error logs which maybe useful for diagnosing errors or give info, notes, or warning notices.

    Note: There's no support provided by me for diagnosing such errors which may occur for various reasons including misconfiguration of installed php/mysql scripts or applications.

    In SSH2 telnet you can use tail command to view the last X number of lines in the file.

    For example for viewing last 10 lines in the file for:

    For Nginx access and error logs:
    Code:
    tail -10 /usr/local/nginx/logs/access.log
    tail -10 /usr/local/nginx/logs/error.log
    
    For specific domainname.com access and error log:
    Code:
    tail -10 /home/nginx/domains/domainname.com/log/access.log
    tail -10 /home/nginx/domains/domainname.com/log/error.log
    
    For other system error logs located at /var/log:

    list /var/log files in ascending time order so the most recently modified files are at the bottom
    Code:
    ls -lhrt /var/log
    
    Code:
    total 2.7M
    -rw------- 1 root root 0 Aug 29 15:33 tallylog
    -rw------- 1 root root 0 Aug 29 15:33 spooler
    drwx------ 3 root root 4.0K Aug 29 15:35 samba
    drwxr-xr-x 2 root root 4.0K Aug 29 15:35 mail
    -rw-r--r-- 1 root 500 0 Oct 8 18:13 dmesg.old
    -rw------- 1 root 500 0 Oct 8 18:13 boot.log
    -rw-r--r-- 1 root 500 0 Oct 8 18:14 dmesg
    drwx------ 2 root root 4.0K Oct 8 18:14 httpd
    drwxr-xr-x 2 root root 4.0K Oct 8 19:08 php-fpm
    -rw-rw---- 1 mysql root 2.3K Oct 9 12:38 mysqld.log
    -rw------- 1 root root 9.2K Oct 26 10:48 yum.log
    -rw------- 1 root utmp 94K Nov 7 22:59 btmp
    drwxr-xr-x 2 root root 4.0K Nov 8 00:00 sa
    -rw------- 1 root root 269K Nov 8 21:39 messages
    -rw------- 1 root root 110K Nov 8 23:08 secure
    -rw-rw-r-- 1 root utmp 43K Nov 8 23:08 wtmp
    -rw-r--r-- 1 root root 144K Nov 8 23:08 lastlog
    -rw------- 1 root root 69K Nov 8 23:08 lfd.log
    -rw------- 1 root root 332K Nov 8 23:08 maillog
    -rw------- 1 root 500 1.6M Nov 8 23:10 cron
    
    For PHP-FPM error log:
    Code:
    tail -10 /var/log/php-fpm/www-error.log
    
    and/or
    Code:
    /var/log/php-fpm/www-php.error.log
    
    For MySQL / MariaDB error log:
    Code:
    tail -10 /var/log/mysqld.log
    
    For CSF firewall LFD log:
    Code:
    tail -10 /var/log/lfd.log
    
    For Mail log:
    Code:
    tail -10 /var/log/maillog
    
    For Cron job logs:
    Code:
    tail -10 /var/log/cron
    

    How to edit php.ini and php-fpm configuration files ?



    Centmin Mod install created command short cuts outlined here to allow you to quickly edit your /usr/local/lib/php.ini file and your /usr/local/etc/php-fpm.conf file. Full list of command shortcuts below:
    • Edit php.ini = phpedit ( /usr/local/lib/php.ini )
    • Edit my.cnf = mycnf ( /etc/my.cnf )
    • Edit php-fpm.conf = fpmconf ( /usr/local/etc/php-fpm.conf )
    • Edit nginx.conf = nginxconf ( /usr/local/nginx/conf/nginx.conf )
    • Edit (nginx) virtual.conf = vhostconf - only edits /usr/local/nginx/conf/conf.d/virtual.conf not the additional vhost domain.com.conf files added later
    • Edit (nginx) php.conf = phpinc ( /usr/local/nginx/conf/php.conf )
    • Edit (nginx) drop.conf = dropinc ( /usr/local/nginx/conf/drop.conf )
    • Edit (nginx) staticfiles.conf = statfilesinc ( /usr/local/nginx/conf/staticfiles.conf )
    • nginx stop/start/restart = ngxstop/ngxstart/ngxrestart
    • php-fpm stop/start/restart = fpmstop/fpmstart/fpmrestart
    • mysql stop/start/restart = mysqlstop/mysqlstart/mysqlrestart
    • nginx + php-fpm stop/start/restart = npstop/npstart/nprestart
    • memcached stop/start/restart =memcachedstop/memcachedstart/memcachedrestart
    • csf stop/start/restart = csfstop/csfstart/csfrestart

    Troubleshooting Tools



    However, there's many linux tools and scripts that can help you figure out what was causing the load issues and when.

    Tools and commands you will want to read up on and learn for basic system admin tasks and troubleshooting.
    Notes:
    However, Centmin Mod users are free to help each other out and ask questions or give answers on this community forum. My hopes are that this community forum evolves so that more veteran long time Centmin Mod users help new Centmin Mod users out :)
     
  3. eva2000

    eva2000 Administrator Staff Member

    28,943
    6,570
    113
    May 24, 2014
    Brisbane, Australia
    Ratings:
    +9,751
    Local Time:
    4:45 PM
    Nginx 1.13.x
    MariaDB 5.5
    oh and unless you're running vB 3.8.9+, PHP 5.5+ and higher might not be supported for lower vBulletin versions so might need to stick with PHP 5.3 for vB 3.8.7 and lower or PHP 5.4 for vB 3.8.7-3.8.8

    If you can use vBulletin 3.8.9 for PHP 5.5 support
     
  4. Mayank

    Mayank New Member

    7
    2
    3
    Sep 8, 2015
    India
    Ratings:
    +2
    Local Time:
    12:15 PM
    1.9
    10.0.21
    Thats a very quick reply and a long post. Ill read now. I was just checking error logs and I see this popping up when I get 502 errors.

    [08-Sep-2015 16:30:31] WARNING: [pool www] child 23593 exited on signal 11 (SIGSEGV) after 2.717061 seconds from start

    Will read your post and try to find out the culprit. Thanks.
     
  5. Mayank

    Mayank New Member

    7
    2
    3
    Sep 8, 2015
    India
    Ratings:
    +2
    Local Time:
    12:15 PM
    1.9
    10.0.21
    That may be an issue. Mine is 3.8.4. Will see if any errors come on WBB board once conversion is completed. Thanks for your help.
     
  6. eva2000

    eva2000 Administrator Staff Member

    28,943
    6,570
    113
    May 24, 2014
    Brisbane, Australia
    Ratings:
    +9,751
    Local Time:
    4:45 PM
    Nginx 1.13.x
    MariaDB 5.5
    signal 11 are segfaults in PHP could also been due to vb incompatibilities with PHP versions as vB 3.8.4 is very old
    never used WBB, so you might want to ask them whether the import requires vB PHP usage itself or if it's just direct file and data transfer/import/manipulation. You may need to downgrade to PHP 5.3 for vB and import to WBB then upgrade PHP both downgrade/upgrade can be done via centmin.sh menu option 5
     
    • Like Like x 1
  7. Mayank

    Mayank New Member

    7
    2
    3
    Sep 8, 2015
    India
    Ratings:
    +2
    Local Time:
    12:15 PM
    1.9
    10.0.21
    I do not get any errors in Burning Board. So it must be PHP problem with Vbulletin 3.8.4. Vbulletin is a good riddance. Was totally annoyed with VB and VBSEO.