最近安装nagios时，检查的的状态都没有什么问题，就是监控系统的状态显示不出来
检测的结果如下：
[root@lb02 ~]# /etc/init.d/httpd start Starting httpd: You have new mail in /var/spool/mail/root [root@lb02 ~]# [root@lb02 ~]# [root@lb02 ~]# /etc/init.d/nagios checkconfig Running configuration check... Nagios Core 3.5.1 Copyright (c) 2009-2011 Nagios Core Development Team and Community Contributors Copyright (c) 1999-2009 Ethan Galstad Last Modified: 08-30-2013 License: GPL Website: http://www.nagios.org Reading configuration data... Read main config file okay... Processing object config file '/usr/local/nagios/etc/objects/commands.cfg'... Processing object config file '/usr/local/nagios/etc/objects/contacts.cfg'... Processing object config file '/usr/local/nagios/etc/objects/timeperiods.cfg'... Processing object config file '/usr/local/nagios/etc/objects/templates.cfg'... Processing object config file '/usr/local/nagios/etc/objects/hosts.cfg'... Processing object config file '/usr/local/nagios/etc/objects/services.cfg'... Processing object config directory '/usr/local/nagios/etc/objects/services'... Read object config files okay... Running pre-flight check on configuration data... Checking services... Checked 12 services. Checking hosts... Checked 2 hosts. Checking host groups... Checked 1 host groups. Checking service groups... Checked 0 service groups. Checking contacts... Checked 1 contacts. Checking contact groups... Checked 1 contact groups. Checking service escalations... Checked 0 service escalations. Checking service dependencies... Checked 0 service dependencies. Checking host escalations... Checked 0 host escalations. Checking host dependencies... Checked 0 host dependencies. Checking commands... Checked 25 commands. Checking time periods... Checked 5 time periods. Checking for circular paths between hosts... Checking for circular host and service dependencies... Checking global event handlers... Checking obsessive compulsive processor commands... Checking misc settings... Total Warnings: 0 Total Errors: 0 Things look okay - No serious problems were detected during the pre-flight check
查看nagios日志的内容：
[root@lb02 var]# tail nagios.log [1536369288] LOG VERSION: 2.0 [1536369288] Finished daemonizing... (New PID=1423) [1536369288] Error: Could not create external command file '/usr/local/nagios/var/rw/nagios.cmd' as named pipe: (2) -> No such file or directory. If this file already exists and you are sure that another copy of Nagios is not running, you should delete this file. [1536369288] Bailing out due to errors encountered while trying to initialize the external command file... (PID=1423) [1536369446] Nagios 3.5.1 starting... (PID=1502) [1536369446] Local time is Sat Sep 08 09:17:26 CST 2018 [1536369446] LOG VERSION: 2.0 [1536369446] Finished daemonizing... (New PID=1503)
错误原因：大致是我不能创建nagios.cmd，到/usr/local/nagios/var目录下竟然发现没有rw目录，创建之后重新加载nagios
[root@lb02 var]# mkdir rw [root@lb02 var]# chown -R nagios.nagios rw [root@lb02 var]# ll total 40 drwxrwxr-x 2 nagios nagios 4096 Sep 6 12:55 archives -rw-r--r-- 1 nagios nagios 5 Sep 8 09:23 nagios.lock -rw-rw-r-- 1 nagios nagios 3991 Sep 8 09:23 nagios.log -rw-r--r-- 1 nagios nagios 17051 Sep 8 09:23 objects.cache -rw-rw-r-- 1 nagios nagios 0 Sep 8 09:23 retention.dat drwxr-xr-x 2 nagios nagios 4096 Sep 8 09:25 rw drwxr-xr-x 3 root root 4096 Sep 6 12:55 spool
此时才加载到正确的监控效果。