安装nagios出现的错误

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.
Copyright (c) - Nagios Core Development Team and Community Contributors
Copyright (c) - Ethan Galstad
Last Modified: --
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  services.
Checking hosts...
    Checked  hosts.
Checking host groups...
    Checked  host groups.
Checking service groups...
    Checked  service groups.
Checking contacts...
    Checked  contacts.
Checking contact groups...
    Checked  contact groups.
Checking service escalations...
    Checked  service escalations.
Checking service dependencies...
    Checked  service dependencies.
Checking host escalations...
    Checked  host escalations.
Checking host dependencies...
    Checked  host dependencies.
Checking commands...
    Checked  commands.
Checking time periods...
    Checked  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:
Total Errors:   

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
[] LOG VERSION: 2.0
[] Finished daemonizing... (New PID=)
[] Error: Could not create external command file '/usr/local/nagios/var/rw/nagios.cmd' as named pipe: () -> 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.
[] Bailing out due to errors encountered while trying to initialize the external command file... (PID=)
[] Nagios 3.5. starting... (PID=)
[] Local time is Sat Sep  :: CST
[] LOG VERSION: 2.0
[] Finished daemonizing... (New PID=)

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
drwxrwxr-x  nagios nagios   Sep   : archives
-rw-r--r--  nagios nagios      Sep   : nagios.lock
-rw-rw-r--  nagios nagios   Sep   : nagios.log
-rw-r--r--  nagios nagios  Sep   : objects.cache
-rw-rw-r--  nagios nagios      Sep   : retention.dat
drwxr-xr-x  nagios nagios   Sep   : rw
drwxr-xr-x  root   root     Sep   : spool

此时才加载到正确的监控效果。