I upgraded from NagiosXI 5.5.5 to NagiosXI 5.5.8 and NagiosXI 5.5.9
However, after Apply Changes OR Config File Management -> Write Configs
nagios.lock path changes to lock_file=/var/run/nagios.lock
Due to this nagios fails to startup.
Jan 21 06:13:41 nagios: Things look okay - No serious problems were detected during the pre-flight check
Jan 21 06:13:41 nagios: Failed to obtain lock on file /var/run/nagios.lock: Permission denied
Jan 21 06:13:41 nagios: Bailing out due to errors encountered while attempting to daemonize... (PID=85978)
@vishfx, /var/run/nagios.lock Is the correct path. They changed it in the latest XI. You can still use the old path if you'd like but paths in all the following locations need to match: