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DGARM Nagios Core - NagiosQL Fix Session Summary

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Source video: DGARM-Nagios-Core-Fixed-NagiosQL-2026-07-17_11-33-20.mkv-2026-07-17_14-24-09.mkv (31 min)

Note on this summary: audio in this recording is largely silent screen-share with
sparse narration, so this summary is reconstructed primarily from on-screen terminal
and browser content (NagiosQL UI, systemd status, shell commands), cross-checked
against the few audible exchanges (a NagiosQL login/root-password exchange).

Summary[edit]

Hands-on troubleshooting session fixing the NagiosQL web front-end on host dcprdlmonitor02, working directly at 10.150.24.167/nagiosql/. NagiosQL 3.5.0 acts as the configuration manager (CCM) in front of Nagios Core, per the plan from the kick-off meeting.

Work observed on screen:

  1. Verified Nagios Core service state via systemctl status nagios.service — confirmed Nagios Core 4.5.9 active/running, config at /usr/local/nagios/etc/nagios.cfg, worker processes healthy.
  2. Diagnosed a NagiosQL write-permission failure: NagiosQL's *Config targets* page (Administration → Config targets) pointed at base directory /etc/nagiosql/ with subdirectories /etc/nagiosql/hosts/, /etc/nagiosql/services/, /etc/nagiosql/backup/ etc. — these directories either didn't exist yet or weren't owned by the web server user, so NagiosQL couldn't write/back up Nagios config files.
  3. Fix applied (via terminal, as root on dcprdlmonitor02):

<syntaxhighlight lang="bash"> 

  sudo mkdir -p /etc/nagiosql/hosts /etc/nagiosql/services \
       /etc/nagiosql/hostgroups /etc/nagiosql/servicegroups
  sudo chown -R apache:apache /etc/nagiosql
  sudo chmod -R 775 /etc/nagiosql

</syntaxhighlight>

  1. Confirmed SELinux was not the blocker — getenforce returned Disabled, so no SELinux context/labeling fix was required (this was checked as a possible cause).
  2. Located the NCPA plugin on disk with locate ncpa, finding /root/nagios-4.5.9/nagios-plugins/plugins-python/check_ncpa.ini — relevant to the Windows-agent monitoring plan discussed in the kick-off meeting.
  3. Used NagiosQL's Configuration Import tool (Administration → Tools → Data import, admin/import.php) to import existing .cfg objects from /usr/local/nagios/etc/objects/ (commands, contacts, templates, switch, printer, localhost, windows, etc.), with "Overwrite database" checked. NagiosQL's own UI states the required import order: commands → timeperiods → contacttemplates → contacts → contactgroups → hosttemplates → hosts → hostgroups → servicetemplates → services → servicegroups.
  4. The engineer cross-referenced the fix steps with an AI assistant chat open on a second monitor/tab, working through the same "web server user lacks write permission on NagiosQL's config directories" diagnosis in parallel (visible in background, not part of the core walkthrough).

Root cause & fix (for the runbook)[edit]

Symptom Root cause Fix
NagiosQL can't write/backup Nagios config files ("cannot open/overwrite config file", "cannot backup — source file missing") /etc/nagiosql/{hosts,services,hostgroups,servicegroups,backup} directories missing or not owned by the web server user mkdir -p the expected directory tree, then chown -R apache:apache + chmod -R 775 on /etc/nagiosql
(Ruled out) SELinux blocking Apache write N/A — SELinux was already Disabled on this host Only check getenforce/apply semanage fcontext + restorecon if SELinux is Enforcing

Source recording[edit]

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