一、监控本地（localhost）内存
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1、上传监控脚本 check_mem 到/usr/local/nagios/libexec
# chown -R nagios.nagios check_mem
# chmod +x check_mem
2、修改commands配置
# vim /usr/local/nagios/etc/objects/commands.cfg
define command{
command_name check_mem
command_line $USER1$/check_mem -w $ARG1$ -c $ARG2$
}3、修改localhost.cfg
# vim /usr/local/nagios/etc/objects/localhost.cfg
define service{
use local-service
host_name localhost
service_description check_mem
check_command check_mem!20!10
}4、重启nagios服务
# service nagios restart
5、check_mem 脚本
#!/bin/bash
USAGE="`basename $0` [-w|--warning] [-c|--critical]"
THRESHOLD_USAGE="WARNING threshold must be greater than CRITICAL: `basename $0` $*"
calc=/tmp/memcalc
percent_free=/tmp/mempercent
critical=""
warning=""
STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3
# print usage
if [[ $# -lt 4 ]]
then
echo ""
echo "Wrong Syntax: `basename $0` $*"
echo ""
echo "Usage: $USAGE"
echo ""
exit 0
fi
# read input
while [[ $# -gt 0 ]]
do
case "$1" in
-w|--warning)
shift
warning=$1
;;
-c|--critical)
shift
critical=$1
;;
esac
shift
done
# verify input
if [[ $warning -eq $critical || $warning -lt $critical ]]
then
echo ""
echo "$THRESHOLD_USAGE"
echo ""
echo "Usage: $USAGE"
echo ""
exit 0
fi
# Total memory available
total=`free -m | head -2 |tail -1 |gawk '{print $2}'`
# Total memory used
used=`free -m | head -2 |tail -1 |gawk '{print $3}'`
# Calc total minus used
free=`free -m | head -2 |tail -1 |gawk '{print $2-$3}'`
# normal values
#echo "$total"MB total
#echo "$used"MB used
#echo "$free"MB free
# make it into % percent free = ((free mem / total mem) * 100)
echo "5" > $calc # decimal accuracy
echo "k" >> $calc # commit
echo "100" >> $calc # multiply
echo "$free" >> $calc # division integer
echo "$total" >> $calc # division integer
echo "/" >> $calc # division sign
echo "*" >> $calc # multiplication sign
echo "p" >> $calc # print
percent=`/usr/bin/dc $calc|/bin/sed 's/^\./0./'|/usr/bin/tr "." " "|/usr/bin/gawk {'print $1'}`
#percent1=`/usr/bin/dc $calc`
#echo "$percent1"
if [[ "$percent" -le $critical ]]
then
echo "CRITICAL - $free MB ($percent%) Free Memory"
exit 2
fi
if [[ "$percent" -le $warning ]]
then
echo "WARNING - $free MB ($percent%) Free Memory"
exit 1
fi
if [[ "$percent" -gt $warning ]]
then
echo "OK - $free MB ($percent%) Free Memory"
exit 0
fi
二、监控客户端内存使用情况
1、上传监控脚本 check_mem 到/usr/local/nagios/libexec
# chown -R nagios.nagios check_mem
# chmod +x check_mem
2、修改nrpe.cfg
# vim /usr/local/nagios/etc/nrpe.cfg
command[check_users]=/usr/local/nagios/libexec/check_users -w 3 -c 5
command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20
command[check_xvda]=/usr/local/nagios/libexec/check_disk -w 10% -c 5% -p /dev/xvda
command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z
command[check_total_procs]=/usr/local/nagios/libexec/check_procs -w 150 -c 200
command[check_xvdb2]=/usr/local/nagios/libexec/check_disk -w 10% -c 5% -p /dev/xvdb2
command[check_swap]=/usr/local/nagios/libexec/check_swap -w 20% -c 10%
command[check_mem]=/usr/bin/sudo /usr/local/nagios/libexec/check_mem -w 20 -c 10 #增加此行
3、在nagios服务器端增加监控服务
# vim /usr/local/nagios/etc/servers/192.168.200.111.cfg
define service{
use generic-service
host_name 192.168.200.111
service_description check_mem
check_command check_nrpe!check_mem
}三、排错
1、NRPE: Unable to read output
（1）为nagios用户增加sudo权限
# visudo
nagios ALL=(ALL) NOPASSWD:/usr/local/nagios/libexec/check_mem
（2）注释掉一下行，表示不需要控制终端
# visudo
#Defaults requiretty
四、nagios监控MySQL
1、check_mysql
nagios监控mysql使用的是 check_mysql 这个插件，需要在nagios服务器上先安装mysql-devel，然后再重新安装nagios-plugin，这样才会出现check_mysql。否则即使copy了一份，也照样用不了。
2、编译或重新编译 nagios-plugin
#yum -y install mysql-devl
#cd nagios-plugins-2.0.3
#./configure --with-nagios-user=nagios --with-nagios-group=nagios
#make && make install
3、查看 check_mysql
# ls /usr/local/nagios/libexec/check_mysql
4、建立专用数据库
# mysql -uroot -p
mysql> create database nagios_monitor;
mysql> grant select on nagios_monitor.* to nagios@'%' identified by '123qaz!@#';
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> select User,Password,Host from mysql.user;
+--------+-------------------------------------------+--------------+
| User | Password | Host |
+--------+-------------------------------------------+--------------+
| root | *B9627CB37815863D1E98D0C41E0233A772355E2B | localhost |
| root | *B9627CB37815863D1E98D0C41E0233A772355E2B | 127.0.0.1 |
| root | *B9627CB37815863D1E98D0C41E0233A772355E2B | ::1 |
| cacti | *BC3E1F14C7940F9C8BCDB05A38385754BB55CD64 | localhost |
| nagios | *BC3E1F14C7940F9C8BCDB05A38385754BB55CD64 | % |
+--------+-------------------------------------------+--------------+
8 rows in set (0.00 sec)
5、check 一下
# /usr/local/nagios/libexec/check_mysql -H 192.168.200.105 -unagios -dnagios_monitor -p 123qaz!@#
# 报了一个错
/usr/local/nagios/libexec/check_mysql: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
# 解决：
ln -sv /usr/local/mysql/lib/libmysqlclient.so.18 /usr/lib64/libmysqlclient.so.18
# 再重新测试
# /usr/local/nagios/libexec/check_mysql -H 192.168.200.111 -unagios -dnagios_monitor -p 123qaz!@#
Uptime: 13991 Threads: 5 Questions: 1242101 Slow queries: 0 Opens: 159 Flush tables: 1 Open tables: 60 Queries per second avg: 88.778|Connections=315c;;; Open_files=85;;; Open_tables=60;;; Qcache_free_memory=16285768;;; Qcache_hits=1210926c;;; Qcache_inserts=16654c;;; Qcache_lowmem_prunes=0c;;; Qcache_not_cached=2c;;; Qcache_queries_in_cache=283;;; Queries=1242101c;;; Questions=1242101c;;; Table_locks_waited=2c;;; Threads_connected=5;;; Threads_running=1;;; Uptime=13991c;;;
6、监控localhost
（1）修改 commands.cfg
# vim /usr/local/nagios/etc/objects/commands.cfg
define command{
command_name check_mysql
command_line $USER1$/check_mysql -H $HOSTADDRESS$ -unagios -dnagios_monitor -p123qaz!@#
}（2）修改 localhost.cfg
# vim /usr/local/nagios/etc/objects/localhost.cfg
define service{
use local-service
host_name localhost
service_description check_mysql
check_command check_mysql
}（3）重启 nagios
# service nagios restart
7、监控客户端
（1）check 一下
# /usr/local/nagios/libexec/check_mysql -H 192.168.200.111 -unagios -dnagios_monitor -p123qaz!@#
（2）客户端修改 nrpe.cfg
# vim /usr/local/nagios/etc/nrpe.cfg
command[check_mysql]=/usr/local/nagios/libexec/check_mysql -H 192.168.200.111 -unagios -dnagios_monitor -p123qaz!@#
（3）重启 nrpe
# killall nrpe
# /usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d
（4）服务端定义服务
# vim /usr/local/nagios/etc/servers/192.168.200.111.cfg
define service{
use generic-service
host_name 192.168.200.111
service_description check_mysql
check_command check_nrpe!check_mysql
}（5）重启 nagios 服务
# service nagios restart
网站题目：nagios监控mysql（check_mysql）及内存使用率（check_mem）
网页路径：
http://njwzjz.com/article/ijhjjs.html
