一、監控本地（localhost）內存
1、上傳監控腳本 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、重啓nagios服務
# service nagios restart
5、check_mem 腳本
#!/bin/bash
USAGE="`basename $0` [-w|--warning]<percent free> [-c|--critical]<percent free>"
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、監控客戶端內存使用情況
1、上傳監控腳本 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服務器端增加監控服務
# 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、排錯
1、NRPE: Unable to read output
（1）爲nagios用戶增加sudo權限
# visudo nagios ALL=(ALL) NOPASSWD:/usr/local/nagios/libexec/check_mem
（2）註釋掉一下行，表示不需要控制終端
# visudo #Defaults requiretty
四、nagios監控mysql
1、check_mysql
nagios監控mysql使用的是 check_mysql 這個插件，需要在nagios服務器上先安裝mysql-devel，然後再重新安裝nagios-plugin，這樣纔會出現check_mysql。否則即使copy了一份，也照樣用不了。
2、編譯或重新編譯 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、建立專用數據庫
# 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!@# # 報了一個錯 /usr/local/nagios/libexec/check_mysql: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory # 解決： ln -sv /usr/local/mysql/lib/libmysqlclient.so.18 /usr/lib64/libmysqlclient.so.18 # 再重新測試 # /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、監控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）重啓 nagios
# service nagios restart
7、監控客戶端
（1）check 一下
# /usr/local/nagios/libexec/check_mysql -H 192.168.200.111 -unagios -dnagios_monitor -p123qaz!@#
（2）客戶端修改 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）重啓 nrpe
# killall nrpe # /usr/local/nagios/bin/nrpe -c /usr/local/nagios/etc/nrpe.cfg -d
（4）服務端定義服務
# 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）重啓 nagios 服務
# service nagios restart