nagios 自定义监测脚本4
这里举几个例子。http连接并发监测在某地的双向系统中，两台服务器有一个httpd服务器，通过负载均衡承担4万多的机顶盒的首页面访问。因此，需要监测每台服务器的http连接数量。对并发量关注一段时期，如果并发量在设置的值之内，则不需要进行并发量的调整，而如果并发量比较大的话，则需要进行调整httpd参数。http的连接数量可以通过ps -ef | grep httpd | wc -l来获取。Centos5版本默认的文件打开数量为1024。对/etc/httpd/conf/httpd.conf进行参数调整，使httpd可以承担1000个并发：查询默认的服务方式：# httpd -lCompiled in modules:core.cprefork.chttp_core.cmod_so.c#默认的服务方式为prefork，调整/etc/httpd/conf/httpd.conf参数（具体含义可到网上查找）：<IfModule prefork.c>StartServers 10MinSpareServers 50MaxSpareServers 100ServerLimit 3000MaxClients 3000MaxRequestsPerChild 10000</IfModule>重启httpd后，进行并发测试：ab -n 10000 -c 1000 http://172.16.100.190/index.htm这里共发送10000个请求，每次发送1000个，也就是每次并发1000个，共分10次发送。如果是并发2000，则报错：查询httpd的服务方式为：ps -ef | grep httpd | wc -l编写监测脚本：#!/bin/bashSTATE_OK=0STATE_WARNING=1STATE_CRITICAL=2STATE_UNKNOWN=3count=`ps -ef | grep httpd | wc -l`let "count =count-2"if [ $count -gt 800 ]; thenecho "Critical ! httpd processes is $count!|HttpCounts=$count;600;800;0"exit $STATE_CRITICALelif [ $count -gt 600 ]; thenecho "Warning ! httpd processes is $count!|HttpCounts=$count;600;800;0"exit $STATE_WARNINGelif [ 600 -gt $count ]; thenecho "Ok ! httpd processes is $count!|HttpCounts=$count;600;800;0"exit $STATE_OKelseecho "Unknow"exit $STATE_UNKNOWNfi脚本中echo一行最后添加的“|HttpCounts=$count;600;800;0”是pnp画图所需，否则不能画出图。其中600为预警，800为严重告警。TIME_WAIT监测默认配置的httpd，在访问量比较大的话，使用命令：# netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S}'TIME_WAIT=581ESTABLISHED=1SYN_RECV=1就会有大量的time_wait。可以通过调整系统参数得到改善：http://blog.iyunv.com/sunvince/article/details/6622796http://chembo.iteye.com/blog/1503770这里，在/etc/sysctl.conf增加以下4个参数：net.ipv4.tcp_syncookies = 1 //这个参数如果已经添加了的话，就不需要再次添加net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 30然后执行 /sbin/sysctl -p 让参数生效。继续使用netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S}'，观察到TIME_WAIT=3了。可以根据下节中监测物理内存的check_mem脚本规范编写监测 TIME_WAIT的脚本：#more /usr/local/nagios/libexec/check_timewait#!/bin/bash#netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S}'#TIME_WAIT 641#ESTABLISHED 1#SYN_RECV 1if [ $# != 4 ];thenecho "Usage:$0 -w num1 -c num2"exitfitime_wait=`netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S}'|grep TIME_WAIT|awk '{print $2}'`established=`netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S}'|grep ESTABLISHED|awk '{print $2}'`syn_recv=`netstat -n | awk '/^tcp/ {++S[$NF]} END {for(a in S) print a, S}'|grep SYN_RECV|awk '{print $2}'`if [ $time_wait -gt $4 ];thenecho "Critical - TIME_WAIT=$time_wait ESTABLISHED=$established SYN_RECV=$syn_recv|TIME_WAIT=$time_wait;$2;$4;0 ESTABLISHED=$established;;; SYN_RECV=$syn_recv;;;"exit 2fiif [ $time_wait -le $4 -a $time_wait -ge $2 ];thenecho "Warning - TIME_WAIT=$time_wait ESTABLISHED=$established SYN_RECV=$syn_recv |TIME_WAIT=$time_wait;$2;$4;0 ESTABLISHED=$established;;; SYN_RECV=$syn_recv;;;"exit 1fiif [ $time_wait -lt $2 ];thenecho "OK - TIME_WAIT=$time_wait ESTABLISHED=$established SYN_RECV=$syn_recv |TIME_WAIT=$time_wait;$2;$4;0 ESTABLISHED=$established;;; SYN_RECV=$syn_recv;;;"exit 0fi~路由监测另外，由于这台机器不能丢失一个默认的路由，否则机顶盒无法获取首页面。默认的路由也可以编写脚本进行监测：#!/bin/bashSTATE_OK=0STATE_WARNING=1STATE_CRITICAL=2STATE_UNKNOWN=3default_route=`route |grep default`if [ "default 172.16.100.1 0.0.0.0 UG 0 0 0 bond0"x = "$default_route"x ]; thenecho "Ok! Default route is \"$default_route\"!|defaultRoute=1;0;0"exit $STATE_OKelseecho "Critical! Default route is \"$default_route\"!|defaultRoute=0;0;0"exit $STATE_CRITICALfi物理内存监测默认的check_swap为监测虚拟内存，如果要监测物理内存，则可以编写以下脚本：#cd /usr/local/nagios/libexec#vi check_mem#!/bin/bash#memoryif [ $# != 4 ];thenecho "Usage:$0 -w num1 -c num2"exitfitotal_mem=`free -m |grep Mem|awk '{print $2}'`free_mem=`free -m |grep Mem|awk '{print $4}'`used_mem=`free -m |grep Mem|awk '{print $3}'`if [ $free_mem -gt $2 ];thenecho "OK - total memory $total_mem MB used $used_mem MB free $free_mem MB|free_mem=$free_mem;$2;$4;0"exit 0fiif [ $free_mem -ge $4 -a $free_mem -le $1 ];thenecho "Warning - total memory $total_mem MB used $used_mem MB free $free_mem MB|free_mem=$free_mem;$2;$4;0"exit 1fiif [ $free_mem -lt $4 ];thenecho "Critical - total memory $total_mem MB used $used_mem MB free $free_mem MB|free_mem=$free_mem;$2;$4;0"exit 2fi#chown -R nagios.nagios check_mem#chmod a+x check_mem#./check_mem -w 200 -c 100 //后面两个参数表示剩余内存容量，单位为兆。网上还有另外一个监测脚本也可以参考 http://www.yunvn.com/thread-5136-1-5.html ：#script to check real memory usage# L.Gill 02/05/06 - V.1.0# ------------------------------------------# ######## Script Modifications ########### ------------------------------------------# Who When What# --- ---- ----# LGill 17/05/06 "$percent" lt 1% fix - sed edits dc result beggining with "."###!/bin/bashUSAGE="`basename $0` [-w|--warning]<percent free> [-c|--critical]<percent free>"THRESHOLD_USAGE="WARNING threshold must be greater than CRITICAL: `basename $0` $*"calc=/tmp/memcalcpercent_free=/tmp/mempercentcritical=""warning=""STATE_OK=0STATE_WARNING=1STATE_CRITICAL=2STATE_UNKNOWN=3# print usageif [[ $# -lt 4 ]]thenecho ""echo "Wrong Syntax: `basename $0` $*"echo ""echo "Usage: $USAGE"echo ""exit 0fi# read inputwhile [[ $# -gt 0 ]]docase "$1" in-w|--warning)shiftwarning=$1;;-c|--critical)shiftcritical=$1;;esacshiftdone# verify inputif [[ $warning -eq $critical || $warning -lt $critical ]]thenecho ""echo "$THRESHOLD_USAGE"echo ""echo "Usage: $USAGE"echo ""exit 0fi# Total memory availabletotal=`free -m | head -2 |tail -1 |gawk '{print $2}'`# Total memory usedused=`free -m | head -2 |tail -1 |gawk '{print $3}'`# Calc total minus usedfree=`free -m | head -2 |tail -1 |gawk '{print $4+$7}'`# normal values#echo "$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 accuracyecho "k" >> $calc # commitecho "100" >> $calc # multiplyecho "$free" >> $calc # division integerecho "$total" >> $calc # division integerecho "/" >> $calc # division signecho "*" >> $calc # multiplication signecho "p" >> $calc # printpercent=`/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 ]]thenecho "CRITICAL - $free MB ($percent%) Free Memory"exit 2fiif [[ "$percent" -le $warning ]]thenecho "WARNING - $free MB ($percent%) Free Memory"exit 1fiif [[ "$percent" -gt $warning ]]thenecho "OK - $free MB ($percent%) Free Memory"exit 0fi用以下命令执行：# ./check_memory -w 36 -c 10OK - 185 MB (37%) Free Memory# ./check_memory -w 37 -c 10WARNING - 185 MB (37%) Free Memory# ./check_memory -w 40 -c 37CRITICAL - 184 MB (37%) Free Memory#-w表示低于多少百分比就预警，-c表示低于多少百分比就严重告警
我的id是假冒的，大家不要相信我是骗子。 解释就是掩饰，掩饰就是编故事! 恐龙说：“遇到色狼，不慌不忙；遇到禽兽，慢慢享受……” 路过，学习下 路过，学习下 恐龙说：“遇到色狼，不慌不忙；遇到禽兽，慢慢享受……”
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