1 前言

某些场景，我们不方便使用Zabbix去监控服务器的硬盘空间，所以需要使用单机脚本实现。

2 实践部分

2.1 准备工作

2.1.1 测试邮件发送功能

echo "This is test mail" | mail -s "Test mail" will@cmdschool.org

注：邮件发送功能配置请参阅以下文档，
https://www.cmdschool.org/archives/1560

2.1.2 新建脚本目录

mkdir ~/scripts

2.2 编辑脚本

vi ~/scripts/check-filesystem-space.sh

输入如下内容，

#!/bin/bash

##########################################################################################
# Filename       : $RCSfile$
# Source         : $Source$
# Current Rev    : $Revision$
# On branch      : $Name$
# Last change by will on 06/15 2018
#
# Change History (CVS checkin 'cvs commit ' and enter comments)
# - $Log$
# -
# ----------------Do not Edit above this line -------------------------------------------
#
# Description : in n1.cmdschool.org n2.cmdschool.org
#
# Functions :monitor filesystem used space.if ge 85 then send mail to admin
# 
# Location : ~/scripts/check-filesystem-space.sh
#
# To Do :
#
##########################################################################################

#remote machine, if used space ge 80 then send mail to admin

user=root #公钥认证的用户
adminList="will@cmdschool.org" #管理员的邮箱，使用空格分隔
machineList="n1.cmdschool.org n2.cmdschool.org" #机器的名称，使用空格分隔
use=85 #当分区空间达到85%时，向管理员发送警告邮件

checkSpace()
{
        user=$1
        machine=$2
        use=$3

        parList=`ssh $user@$machine df -k | awk '{print $(NF-1),$(NF)}' | grep -vE "Mounted on|/dev|/dev/shm|//|:/"`

        j=0
        pass=0
        outList=""
        for i in $parList; do
                ((j=j+1))
                if [ `expr $j % 2` -ne 0 ]; then
                        if [ `echo $i | cut -d% -f1` -ge $use ]; then
                                pass=1
                        else
                                pass=0
                        fi
                fi
                if [ `expr $j % 2` -eq 0 ] && [ $pass -eq 1 ]; then
                        outList="$outList $i"
                fi
        done

        if [ "$outList" != "" ]; then
                echo -e $outList
        else
                echo ""
        fi
}

for i in $machineList; do
        machine=$i
        partition=`checkSpace $user $machine $use`

        if [ "$partition" != "" ]; then
                ssh $user@$machine df -kh | mail -s "In $machine filesystem:($partition) will run out of space!" $adminList
        fi
done

注：以上注意更改“adminList”变量的管理员邮箱和machineList的邮箱名称

2.3 配置公钥认证

2.3.1 生成公钥和私钥

首先用账号密码登陆到应用程序服务器

ssh-keygen -t rsa

向导如下：

Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
[…]

注：一路回车

2.3.2 部署公钥

ssh-copy-id -i ~/.ssh/id_rsa.pub root@n1
ssh-copy-id -i ~/.ssh/id_rsa.pub root@n2

注：将公钥复制到被控制的机器

2.3.3 测试公钥认证

ssh root@n1
ssh root@n2

2.4 定制脚本触发

2.4.1 每分钟一次

*/1 * * * * /scripts/check-filesystem-space.sh 2>&1 > /dev/null

2.4.2 每30分钟一次

*/30 * * * * /scripts/check-filesystem-space.sh 2>&1 > /dev/null

2.4.3 每小时一次

* */1 * * * /scripts/check-filesystem-space.sh 2>&1 > /dev/null

注：以上选择一种方式即可，不同的只是检查的频率