SHELL编程：cpu100%时自动重启Nginx脚本

shell读取CPU使用率，在连续9秒内CPU高于 98% 时自动重启 Nginx

 

shell的浮点数比较 ： $(echo "$CPU_STATUS > 98"|bc) = 1

 

#!/bin/sh# toontong @ 2010-09-20# @kingsoft.comnginx_bin=/usr/local/nginx/sbin/nginxisExitsNginx(){ ps aux | grep nginx | grep -vc "grep"}function_kill_nginx(){ while [ `isExitsNginx` /> 0 ] do kill -QUIT $(ps -ef |grep nginx | grep -v "grep" | awk -F ' ' '{print $2}') sleep 0.1 done printf '/n' date printf "kill nginx done./n"}function_start_nginx(){ if [ `isExitsNginx` /> 0 ]; then printf "Nginx is running..../n" exit -1 fi ${nginx_bin} -v -t ${nginx_bin} sleep 0.2 if [ `isExitsNginx` /> 0 ]; then printf "Nginx start..../n" else printf "error...Nginx not run./n" exit -2 fi}function_cpu_used_rate(){ ##echo user nice system idle iowait irq softirq CPULOG_1=$(cat /proc/stat | grep 'cpu ' | awk '{print $2" "$3" "$4" "$5" "$6" "$7" "$8}') SYS_IDLE_1=$(echo $CPULOG_1 | awk '{print $4}') Total_1=$(echo $CPULOG_1 | awk '{print $1+$2+$3+$4+$5+$6+$7}') sleep 2 CPULOG_2=$(cat /proc/stat | grep 'cpu ' | awk '{print $2" "$3" "$4" "$5" "$6" "$7" "$8}') SYS_IDLE_2=$(echo $CPULOG_2 | awk '{print $4}') Total_2=$(echo $CPULOG_2 | awk '{print $1+$2+$3+$4+$5+$6+$7}') SYS_IDLE=`expr $SYS_IDLE_2 - $SYS_IDLE_1` Total=`expr $Total_2 - $Total_1` SYS_USAGE=`expr $SYS_IDLE/$Total*100 |bc -l` #echo $SYS_USAGE SYS_Rate=`expr 100-$SYS_USAGE |bc -l` Disp_SYS_Rate=`expr "scale=3; $SYS_Rate/1" |bc` echo $Disp_SYS_Rate}CPU_STATUS=-1cnt=0while true ; do CPU_STATUS=`function_cpu_used_rate`# echo $CPU_STATUS if [ $(echo "$CPU_STATUS > 98"|bc) = 1 ];then cnt=`expr $cnt + 1` else cnt=0 fi if [ $cnt /> 2 ]; then function_kill_nginx function_start_nginx fi sleep 1done