Applicable to:
- Plesk for Linux
Symptoms
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The nginx service fails to start/reload with the following error in the
/var/log/nginx/error.logfile:CONFIG_TEXT: nginx: [emerg] open() "/var/www/vhosts/system/example.com/logs/proxy_access_ssl_log" failed (24: Too many open files)
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Some or all websites are not accessible
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Warning is shown in the Tools & Settings > Diagnose & repair:
PLESK_WARN: Checking for nginx ULIMIT value N domains have been found on server. Problem with nginx default limit for open files is possible
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NodeJS and Ruby web applications are showing 502 Bad Gateway error when performing some Plesk tasks such as creating domains, subscriptions, changes on Apache or Nginx, etc:
CONFIG_TEXT: Server Error
502 Bad Gateway
Web server received an invalid response while acting as a gateway or proxy server. -
After installing a new certificate for the domain, the old one is still shown in a web browser, however, the correct certificate is selected at the Domains > example.com > Hosting Settings page.
Cause
Nginx's virtual host opens 4 log files for each virtual host with physical hosting:
- proxy_access_log
- proxy_access_ssl_log
- webmail_access_log
- webmail_access_ssl_log
As a result of this fact, the maximum number of open files is exceeded by the nginx server due to a big number of domains (usually, more than 100).
Resolution
Before applying the solution, verify the environment against: https://webpros.atlassian.net/wiki/spaces/~60353f40d416ea0070f67141/pages/4465918388 and file a 3rdline if needed.
3rd line will be needed if the result of:
grep 'Max open files' /proc/$(cat /var/run/nginx.pid)/limits |awk {'print $4'}
Is different than the result of:
plesk php -r 'require "sdk.php"; print_r(get_param("ulimit"));'
After restarting nginx
# systemctl restart nginx
BUT, if the above condition is met, and the following count is more than 2
$ulimit / Plesk_Config::get()->webserver->ulimit->openedFilesPerDomain) / $domainsCount
Then is working by design and manual solution should be applied.
Warning: Execution of the websrv_ulimits utility without --no-restart option initiates rebuilding of web configuration files for all domains and can cause significant downtime in case of a big number of hosted websites.
Execute the command during the maintenance time frame.
It is good practice to set open files limit value more than number of domains in Plesk * 16 at least. In example below provided actions how to set limit to 4096:
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Connect to the server via SSH
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Set open files limit to 4096 for both Apache and Nginx:
# /usr/local/psa/admin/sbin/websrv_ulimits --set 4096 --no-restart
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Restart Apache and nginx services at Plesk > Tools & Settings > Services Management to apply changes.
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Check that 'Max open files limit' was applied properly, after web services restarting:
# grep 'Max open files' /proc/$(cat /var/run/nginx.pid)/limits
Max open files 4096 4096 file -
If the solution above did not help, set the limit using the
ulimitutility:# ulimit -n 4096
Comments
2 comments
Me sigue mostrando el error
The error persists:
# ulimit
unlimited
# grep 'Max open files' /proc/$(cat /var/run/nginx.pid)/limits
Max open files 40960 40960 files
# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: [emerg] open() "/var/www/vhosts/system/<REDACTED>/logs/proxy_access_ssl_log" failed (24: Too many open files)
nginx: configuration file /etc/nginx/nginx.conf test failed
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