nagios 自带的Plugin  check_log监控日志比较单一，对于对日志监控比较高的生产环境下还是不行的。
consol.de 出的check_logfile很不错很强大，支持正则表达式。详细官方说明如下:
http://labs.consol.de/lang/de/nagios/check_logfiles/
我以监控apache日志为例说明下这个怎么用。
wget    http://labs.consol.de/wp-content/uploads/2012/02/check_logfiles-3.4.7.1.tar.gz
tar xf check_logfiles-3.4.7.1.tar.gz
cd check_logfiles-3.4.7.1
./configure --prefix=/usr/local/nagios/ --with-nagios-user=nagios --with-nagios-group=nagios --with-seekfiles-dir=/usr/local/nagios/var/tmp/ --with-protocols-dir=/usr/local/nagios/var/tmp/ --with-perl=/usr/bin/perl --with-gzip=/bin/gzip
make && make install
###########################
#我们利用调用文件来监控，这样方便些
#创建log.conf
vim /usr/local/nagiso/etc/log.conf
@searches = (
{
    tag => 'test_http',
    logfile => '/var/log/httpd/access_log',
rotation => 'CentOs',
    criticalpatterns => [
     '.*401\s*571.*',

    ],
warningpatterns => [
     '404'
    ]

},
);
#具体的详细配置可以看下官方介绍
在nrpe添加
command[check_logfiles]=/usr/local/nagios/libexec/check_logfiles --config=/usr/local/nagios/etc/log.cfg 
#执行
/usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d
好了被监控端配置完成了
被监控端services.cfg 
    
    
    
    

     
     
     
     

      
      
      
      define service {
      
      
      
      
                host_name     nagios_test
      
      
      
      
                service_description     chech_sanlogs
      
      
      
      
             use generic-service,srv-pnp
      
      
      
      
                check_period                    24x7
      
      
      
      
                max_check_attempts        4
      
      
      
      
                normal_check_interval 1
      
      
      
      
                retry_check_interval 1
      
      
      
      
                contact_groups                nagcmd
      
      
      
      
                notification_interval     10
      
      
      
      
                notification_period         24x7
      
      
      
      
                notification_options        w,u,c,r
      
      
      
      
                check_command        check_log!20!check_logfiles
      
      
      
      
             }
      
      
      
      
vim etc/objects/commands.cfg
      
      
      
      
define command{
      
      
      
      
                 command_name check_log
      
      
      
      
                 command_line $USER1$/check_nrpe -H $HOSTADDRESS$ -t $ARG1$ -c $ARG2$
      
      
      
      
                 }
     
     
     
     

    
    
    
    

##重启下nagios,就OK了
正常状态：
告警状态
配合下图表看起来更方便