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。
实现原理：
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。
#!/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="${ROOT}/logs/load.log"
# 通知电邮列表
NOTICE_EMAIL=‘[email protected]‘
# cpu,memory,load average 记录上一次发送通知电邮时间
CPU_REMARK=‘/tmp/servermonitor_cpu.remark‘
MEM_REMARK=‘/tmp/servermonitor_mem.remark‘
LOAD_REMARK=‘/tmp/servermonitor_loadaverage.remark‘
# 发通知电邮间隔时间
REMARK_EXPIRE=3600
NOW=$(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)" > "$MEM_REMARK"
fi
}
# 获取load average
function GetLoad() {
load=$(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