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Nagios troubleshooting

Nagios not working after Debian upgrade?

Apache is probably not executing php files properly. Make sure the apache modules are enabled. Screenshots of error: Firefox (something probably cached from before)

Chrome fresh navigation to page Run:

a2enmod php7.3

List of modules that should be enabled

# apachectl -M

Loaded Modules:
 core_module (static)
 so_module (static)
 watchdog_module (static)
 http_module (static)
 log_config_module (static)
 logio_module (static)
 version_module (static)
 unixd_module (static)
 access_compat_module (shared)
 alias_module (shared)
 auth_basic_module (shared)
 authn_core_module (shared)
 authn_file_module (shared)
 authz_core_module (shared)
 authz_host_module (shared)
 authz_user_module (shared)
 autoindex_module (shared)
 cgi_module (shared)
 cgid_module (shared)
 deflate_module (shared)
 dir_module (shared)
 env_module (shared)
 filter_module (shared)
 mime_module (shared)
 mpm_prefork_module (shared)
 negotiation_module (shared)
 php7_module (shared)
 reqtimeout_module (shared)
 rewrite_module (shared)
 setenvif_module (shared)
 status_module (shared)

Debian 11

apt install libapache2-mod-php7.4

Tested on

  • Debian 10 (after upgrade from Debian 9)

nagiosgraph js problem

When accessing graphs in url you get an error

JavaScript is disabled.
nagiosgraph.js is not installed or wrong version.

The issue could be in rrd filename (/usr/local/nagiosgraph/var/rrd) encoding the '“' character as ”%22“ which confuses javascript. Example of filename

Simply remove the offending file and reload nagios.

Tested on

  • nagios 4.2.2
  • nagiosgraph 1.5.2
  • Debian GNU/Linux 11 (bullseye)

CHECK_NRPE: (ssl_err != 5) Error - Could not complete SSL handshake with <server_ip>

Make sure you are using an up to date nrpe plugins.

Tested on

  • Debian 10 (after upgrade from Debian 9)

Cannot get interface speed using highperf mib : UNKNOWN

Add to check_if_traffic -g2 flag:

check_if_traffic!22!localhost!public!eth0!0,50000!0,75000!-Y -B -k -g2 --label

Settings not applied after restart

For example if changing whether or not notifications will be sent, nagios by default remembers state even after restart, so for notifications you will need to change it manually in /usr/local/nagios/var/retention.dat.

You could also remove this file (but first stop nagios and make a backup!) which will force reread of all configs and schedule the check for all hosts and services, so make sure you want this.

See also


wiki/nagios_troubleshooting.txt · Last modified: 2023/09/22 11:57 by antisa

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