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Overview
This KB article provides steps on optimizing the PHP settings file php.ini on your Nagios XI server. There are certain situations where the default settings in PHP need increasing to improve the features of Nagios XI on larger systems.
PHP is the scripting language that is used to provide the Nagios XI web pages.
Editing Files
In many steps of this article you will be required to edit files. This documentation will use the vi text editor. When using the vi
editor:
-
To make changes press i on the keyboard first to enter insert mode
-
Press Esc to exit insert mode
-
When you have finished, save the changes in vi by typing :wq and press Enter
php.ini File Location
To determine the location of your php.ini file execute the following command:
find /etc -name php.ini
If there are multiple results then the one in the apache directory is the one that needs changing.
In this KB article, after making a change to the php.ini file you will need to restart the Apache service using one of the commands below:
RHEL 7 | CentOS 7 | Oracle Linux 7
systemctl restart httpd.service
Debian | Ubuntu 16/18
systemctl restart apache2.service
max_input_vars
This is the most common setting that needs adjusting. There is a default limit of 1000 that exists to prevent denial of service attacks that can occur.
When viewing the Apache httpd error log:
tail /var/log/httpd/*rror_log
You will see an event like the following:
[Tue Jun 30 18:16:34.132636 2015] [:error] [pid 16785] [client 10.25.254.50:28694] PHP Warning: Unknown: Input variables exceeded 1000.
To increase the limit change max_input_vars in php.ini.
To increase the value, edit the php.ini file and check to see if the option already exists in the php.ini file by typing this command in vi:
/max_input_vars
If the option does not exist the following message will be displayed:
E486: Pattern not found: max_input_vars
If the option does not exist then it's a simple matter of adding the line to the end of the file. Press Shift + G to jump to the end of the file.
If the option does exist then it will take you directly to that line which you can adjust.
Define the limit to a larger number like 50000:
max_input_vars = 50000
After making the changes save the file and then restart the httpd service.
Once the service has been restarted go and check to see if this has resolved your problem. If it has not resolved the problem, check the logs again to see if you are still hitting a limit. If you are, repeat the steps above to increase the value to a larger number like 100000.
memory_limit
In larger Nagios XI deployments the amount of memory that PHP requires may exceed the default limit of 128M. This setting exists to prevent a poorly written script from eating up all available memory on a server.
When viewing the Apache httpd error log:
tail /var/log/httpd/*rror_log
You will see an event like the following:
[Tue Jul 12 02:22:07 2016] [error] [client 10.25.254.50] PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 354 bytes)
in /usr/local/nagiosxi/html/backend/includes/xml2json.php on line 243
To increase the value, edit the php.ini file and check to see if the option already exists in the php.ini file by typing this command in vi:
/memory_limit
If the option does not exist the following message will be displayed:
E486: Pattern not found: memory_limit
If the option does not exist then it's a simple matter of adding the line to the end of the file. Press Shift + G to jump to the end of the file.
If the option does exist then it will take you directly to that line which you can adjust.
Define the limit to a larger number like 1024M:
memory_limit = 1024M
After making the changes save the file and then restart the httpd service.
Once the service has been restarted go and check to see if this has resolved your problem. If it has not resolved the problem, check the logs again to see if you are still hitting a limit. If you are, repeat the steps above to increase the value to a larger number like 2048M.
max_execution_time
In larger Nagios XI deployments the PHP engine may take a while to execute. There is a default limit of 30 seconds that exists to prevent a poorly written script from locking up the server.
When viewing the Apache httpd error log:
tail /var/log/httpd/*rror_log
You will see an event like the following:
Fatal error: Maximum execution time of 30 seconds exceeded
To increase the value, edit the php.ini file and check to see if the option already exists in the php.ini file by typing this command in vi:
/max_execution_time
If the option does not exist the following message will be displayed:
E486: Pattern not found: max_execution_time
If the option does not exist then it's a simple matter of adding the line to the end of the file. Press Shift + G to jump to the end of the file.
If the option does exist then it will take you directly to that line which you can adjust.
Define the limit to a larger number like 120:
max_execution_time = 120
After making the changes save the file and then restart the httpd service.
Once the service has been restarted go and check to see if this has resolved your problem. If it has not resolved the problem, check the logs again to see if you are still hitting a limit. If you are, repeat the steps above to increase the value to a larger number like 180.
max_input_time
In larger Nagios XI deployments the PHP engine may take a while to execute. The default setting is -1, this means that the value from the max_execution_time setting is used instead. This setting exists to prevent a poorly written script from locking up the server.
When viewing the Apache httpd error log:
tail /var/log/httpd/*rror_log
You will see an event like the following:
Fatal error: Maximum input time of 30 seconds exceeded
To increase the value, edit the php.ini file and check to see if the option already exists in the php.ini file by typing this command in vi:
/max_input_time
If the option does not exist the following message will be displayed:
E486: Pattern not found: max_input_time
If the option does not exist then it's a simple matter of adding the line to the end of the file. Press Shift + G to jump to the end of the file.
If the option does exist then it will take you directly to that line which you can adjust.
Define the limit to a larger number like 300:
max_input_time = 300
After making the changes save the file and then restart the httpd service.
Once the service has been restarted go and check to see if this has resolved your problem. If it has not resolved the problem, check the logs again to see if you are still hitting a limit. If you are, repeat the steps above to increase the value to a larger number like 600.
Error Reporting
If you find that there are PHP notices and deprecated messages accumulating in the error log, see Turning Off PHP Notices and Deprecated Messages.
Additional Resources
The online documentation for PHP explains these settings in more detail, please refer to the following links:
Description of core php.ini directives
Final Thoughts
For any support related questions please visit the Nagios Support Forums at:
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