shell 监控cpu，memory，load average，记录到log，当负载压力时，发电邮通知管理员。

原理：

1.获取cpu，memory，load average的数值

2.判断数值是否超过自定义的范围，例如（CPU>90%，Memory<10%，load average>2）

3.如数值超过范围，发送电邮通知管理员。发送有时间间隔，每小时只会发送一次。

4.将数值写入log。

5.设置crontab 每30秒运行一次。

ServerMonitor.sh

#!/bin/bash# 系统监控,记录cpu、memory、load average,当超过规定数值时发电邮通知管理员# *** config start ***# 当前目录路径ROOT=$(cd "$(dirname "$0")"; pwd)# 当前服务器名HOST=$(hostname)# log 文件路径CPU_LOG="${ROOT}/logs/cpu.log"MEM_LOG="${ROOT}/logs/mem.log"LOAD_LOG="${ROOT}/logs/load.log"# 通知电邮列表NOTICE_EMAIL='admin@admin.com'# cpu,memory,load average 记录上一次发送通知电邮时间CPU_REMARK='/tmp/servermonitor_cpu.remark'MEM_REMARK='/tmp/servermonitor_mem.remark'LOAD_REMARK='/tmp/servermonitor_loadaverage.remark'# 发通知电邮间隔时间REMARK_EXPIRE=3600NOW=$(date +%s)# *** config end ***# *** function start ***# 获取CPU占用function GetCpu() {    cpufree=$(vmstat 1 5 |sed -n '3,$p' |awk '{x = x + $15} END {print x/5}' |awk -F. '{print $1}')    cpuused=$((100 - $cpufree))    echo $cpuused    local remark    remark=$(GetRemark ${CPU_REMARK})    # 检查CPU占用是否超过90%    if [ "$remark" = "" ] && [ "$cpuused" -gt 90 ]; then        echo "Subject: ${HOST} CPU uses more than 90% $(date +%Y-%m-%d' '%H:%M:%S)" | sendmail ${NOTICE_EMAIL}        echo "$(date +%s)" > "$CPU_REMARK"    fi}# 获取内存使用情况function GetMem() {    mem=$(free -m | sed -n '3,3p')    used=$(echo $mem | awk -F ' ' '{print $3}')    free=$(echo $mem | awk -F ' ' '{print $4}')    total=$(($used + $free))    limit=$(($total/10))    echo "${total} ${used} ${free}"    local remark    remark=$(GetRemark ${MEM_REMARK})    # 检查内存占用是否超过90%    if [ "$remark" = "" ] && [ "$limit" -gt "$free" ]; then        echo "Subject: ${HOST} Memory uses more than 90% $(date +%Y-%m-%d' '%H:%M:%S)" | sendmail ${NOTICE_EMAIL}        echo "$(date +%s)" > "$MEM_REMARK"    fi}# 获取load averagefunction GetLoad() {    load=$(uptime | awk -F 'load average: ' '{print $2}')    m1=$(echo $load | awk -F ', ' '{print $1}')    m5=$(echo $load | awk -F ', ' '{print $2}')    m15=$(echo $load | awk -F ', ' '{print $3}')    echo "${m1} ${m5} ${m15}"    m1u=$(echo $m1 | awk -F '.' '{print $1}')    local remark    remark=$(GetRemark ${LOAD_REMARK})    # 检查是否负载是否有压力    if [ "$remark" = "" ] && [ "$m1u" -gt "2" ]; then        echo "Subject: ${HOST} Load Average more than 2 $(date +%Y-%m-%d' '%H:%M:%S)" | sendmail ${NOTICE_EMAIL}        echo "$(date +%s)" > "$LOAD_REMARK"    fi}# 获取上一次发送电邮时间function GetRemark() {    local remark    if [ -f "$1" ] && [ -s "$1" ]; then        remark=$(cat $1)        if [ $(( $NOW - $remark )) -gt "$REMARK_EXPIRE" ]; then            rm -f $1            remark=""        fi    else        remark=""    fi    echo $remark}# *** function end ***cpuinfo=$(GetCpu)meminfo=$(GetMem)loadinfo=$(GetLoad)echo "cpu: ${cpuinfo}" >> "${CPU_LOG}"echo "mem: ${meminfo}" >> "${MEM_LOG}"echo "load: ${loadinfo}" >> "${LOAD_LOG}"exit 0

crontab

* * * * * /home/xxxx/ServerMonitor.sh* * * * * sleep 30; /home/xxxx/ServerMonitor.sh