check_external_commands = 1 （enable  commands  file）
command_check_interval = -1 （check  the  external  command file as often as possible ）

define service{
        name                            passive_service
        use                             generic-service
        max_check_attempts              3
        active_checks_enabled           0
        passive_checks_enabled          1
        normal_check_interval           5
        retry_check_interval            1
        notifications_enabled           1
        notification_interval           5
        notification_period             24x7
        contact_groups                  admins
        register                        0
}

define command{
        command_name                    check_dummy
        command_line                    /usr/local/nagios/libexec/check_dummy $ARG1$
}

define service{
        use                             passive_service
        host_name                       localhost   #本机被动监控
        service_description             NSCA
        check_command                   check_dummy!0
        notifications_enabled           1
}

server_address=xxx.xxx.xxx.xxx （这里务必使用对外表现的IP）
debug=1                       （debug选项即log选项，写入message）
aggregate_writes=1            （能够支持更大的监控量，建议开启）
max_packet_age=60             （数据包过期时间，默认30s，但是考虑到网络因素建议设为60s）
password=xxxxxxx              （密码，最基础的加密方式，也可以不设置）

#!/bin/bash
 
#初始化并设置阀值
HOSTNAME=$(hostname)
DIR=/tmp/nsca
[ -d "$DIR" ] || mkdir -p $DIR
>${DIR}/nsca_messages.txt
 
IP=$(ifconfig eth0|grep 'inet addr'|sed 's/.*addr:\(.*\) Bcast:.*/\1/')
HOSTNAME=$(hostname)
 
CPU_MAX=90          #单个进程的cpu使用率
UPTIME_MAX=8     #系统负载
DISK_MAX=95          #磁盘使用率
 
#设置一个flag，用于脚本的执行与否；0执行，1不执行
#FLAG=$(cat /root/tool/flag.txt)
#[ $FLAG -eq 1 ] && { exit 1 }
 
#进程占用cpu情况
CPU_MAX_NUM=$(top -n 1 -b|awk 'NR>7{if ($10>"'$CPU_MAX'")print  $10}'|wc -l)     #统计cpu使用率超过90%的进程数
if [ "$CPU_MAX_NUM" -gt 0 ];then
     sleep 5
     CPU_MAX_NUM=$(top -n 1|awk 'NR>7{if ($10>"'$CPU_MAX'")print  $10}'|wc -l)
        [ $CPU_MAX_NUM -gt 0 ] && $(echo "CPU_${CPU_MAX}%_NUM: $CPU_MAX_NUM" >>${DIR}/nsca_messages.txt)
fi
 
 
#系统负载
UPTIME=$(uptime|sed 's/.*age: \(.*\),.*,.*/\1/'|awk -F'.' '{print $1}')
[ "$UPTIME" -gt "$UPTIME_MAX" ] && $(echo "UPTIME: $UPTIME" >>${DIR}/nsca_messages.txt)
 
#监控磁盘空间
DISK=$(df -h |awk 'NR>1{print $0}'|sort -k5|tail -1|awk '{print $1,$4,$5}')          #提取磁盘占用率最大的分区
DISK_USAGE=$(echo $DISK|awk '{print $3}'|tr -d '%')
[ "$DISK_USAGE" -ge "$DISK_MAX" ] && $(echo "DISK: $DISK" >> ${DIR}/nsca_messages.txt)
 
#监控文件系统（filesystem）
[ -f "${DIR}/fs.txt" ] || $(df -T|grep -v tmpfs|awk 'NR>1{print $1,$2}'>${DIR}/fs.txt)
while read FS
do
     PARTITION=$(echo $FS|awk '{print $1}')     #提取分区名
     FILESYSTEM=$(echo $FS|awk '{print $2}')     #提取文件系统类型
     [ "$FILESYSTEM" == "ext4" ] && CMD="/sbin/tune4fs" || CMD="/sbin/tune2fs"
     FS_STAT=$($CMD -l $PARTITION | grep 'Filesystem state')
     echo $FS_STAT|grep 'clean$'>/dev/null
     if [ $? -eq 1 ];then
          echo "$PARTITION : $FS_STAT" >>${DIR}/nsca_messages.txt
     fi
done< ${DIR}/fs.txt
 
#监控iptables
#/sbin/iptables -nL|grep 'INPUT'|grep 'policy ACCEPT' && echo "iptables: policy DROP">>${DIR}/messages.txt
 
#发送警报邮件
#if [ -s ${DIR}/messages.txt ];then          #如果messages.txt文件不为空则发送警报信
#     mail -s "system monitor: $IP  $HOSTNAME" "$ADMIN_SMS" < ${DIR}/messages.txt
#fi
 
if [ -s ${DIR}/nsca_messages.txt ];then
     MESS=$(cat ${DIR}/nsca_messages.txt)
     echo "$HOSTNAME;NSCA;2;$MESS"|/root/mailtool/nsca/send_nsca -H 199.15.116.25 -d ";" -c send_nsca.cfg>>send_stat.txt
else
     echo "$HOSTNAME;NSCA;0;OK"|/root/mailtool/nsca/send_nsca -H 199.15.116.25 -d ";" -c send_nsca.cfg>>sent_stat.txt
fi

#!/bin/bash
#made by caishzh
#
 
if [ -z "$1" ] || [ -z "$2" ];then
     echo -e "\nUsage:\n   $0 groupname filename"
     echo -e "Example:\n   $0 webserver /root/webserver.txt\n"
     exit 1
fi
 
NAGIOS_DIR="/usr/local/nagios"
 
HOSTGROUP=$1
SERVICES=$2
while read LINE
do
HOSTNAME=$(echo $LINE|awk '{print $1}')
IP=$(echo $LINE|awk '{print $2}')
 
cat >>"$NAGIOS_DIR"/etc/nsca/"$HOSTGROUP".cfg < <eof
define host{
     use             linux-server
     host_name          $HOSTNAME
     address          $IP
}
define service{
        use                             passive_service
        host_name                       $HOSTNAME
        service_description             NSCA
        check_command                   check_dummy!0
        notifications_enabled           1
}
EOF
done<$SERVICES

service1 192.168.1.1
service2 192.168.1.2