Keepalived & LVS: 实现web的负载均衡和高可用

1. 环境介绍

A. 192.168.205.111 steppingstone.glinux.top steppingstone
B. 192.168.205.112 rs1.glinux.top rs1
C. 192.168.205.118 rs2.glinux.top rs2
D. 192.168.205.113 ha1.glinux.top ha1
E. 192.168.205.115 ha2.glinux.top ha2
F. alias自定义

　　vim /root/.bashrc

alias echop='for i in `seq 1 $COLUMNS`; do echo -n "+"; done'
alias rs='for i in {1..2}; do ssh rs$i'
alias ha='for i in {1..2}; do ssh ha$i'

2. LVS DR模型中Realserver上的准备

A. [root@steppingstone ~]# rs ' cd /proc/sys/net/ipv4/conf/; pwd'; echop; done
B. [root@steppingstone ~]# rs 'echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce'; echop; done #修改arp_announce
C. [root@steppingstone ~]# rs 'echo 2 > /proc/sys/net/ipv4/conf/eth0/arp_announce'; echop; done
D. [root@steppingstone ~]# rs 'echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore'; echop; done
E. [root@steppingstone ~]# rs ' echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore'; echop; done
F. [root@steppingstone ~]# rs 'ifconfig lo:0 192.168.205.80 broadcast 192.168.205.80 netmask 255.255.255.255 up; ifconfig lo:0'; echop; done #配置vip地址
H. [root@steppingstone ~]# rs 'yum install httpd; echo "<h1>`uname -n`</h1>"> /var/www/html/index.html; service httpd restart'; echop; done #安装web服务

3. ha上的准备

A. [root@steppingstone ~]# ha 'yum install keepalived -y'; echop; done #安装keepalived
B. [root@steppingstone ~]# ha 'yum install ipvsadm -y'; echop; done #安装ipvsadm

4. 配置keepalived

A. [root@ha2 ~]# man keepalived.conf #查看帮助文档
B. [root@ha1 keepalived]# vim keepalived.conf

 ! Configuration File for keepalived

 global_defs {

 notification_email {

 #指定故障发生时通告给的邮件地址

 xxxxx@.com

 }

 #发送者信息

 notification_email_from xxxxxx@.com

 smtp_server smtp..com

 smtp_connect_timeout

 router_id LVS_DEVEL

 }

 vrrp_script chk_schedown {

 #此处可自定义检测脚本, 0表示测试成功,此处以检测是否存在改文件做测试

 script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"

 #每两秒检测一次

 interval

 #如果失败, 优先级减去多少

 weight -

 #失败检测次数,失败2次才是失败

 fall

 #成功一次, 即时成功

 rise

 }

 vrrp_instance VI_1 {

 #定义vrrp虚拟路由

 state MASTER

 #定义工作的物理接口

 interface eth0

 #两台ha上的虚拟路由id要保持一致

 virtual_router_id

 #优先级要比备节点大

 priority

 advert_int

 #定义认证码

 authentication {

 #认证类型为简单字符认证

 auth_type PASS

 auth_pass keepalivedpass

 }

 #定义提供服务的虚拟ip

 virtual_ipaddress {

 192.168.205.80/ dev eth0 label eth0:

 }

 #定义要检查的脚本

 track_script {

 chk_schedown

 }

 #定义keepalived节点转换通知

 notify_master "/etc/keepalived/keepalived_notify.sh master 192.168.205.80"

 notify_backup "/etc/keepalived/keepalived_notify.sh backup 192.168.205.80"

 notify_fault "/etc/keepalived/keepalived_notify.sh fault 192.168.205.80"

 }

 #定义vitual_server

 virtual_server 192.168.205.80  {

 delay_loop

 lb_algo rr

 lb_kind DR

 nat_mask 255.255.255.0

 #指定是否使用长连接

 #persistence_timeout

 protocol TCP

 sorry_server 127.0.0.1

 #指定realserver rs1,

 # HTTP_GET|SSL_GET|TCP_CHECK|SMTP_CHECK|MISC_CHECK, 可分别针对于http, https, mysql, mail等进行健康状况监测

 real_server 192.168.205.112  {

 weight

 HTTP_GET {

 url {

 path /

 #http返回状态为200, 说明状态ok

 status_code

 }

 #定义超时时间

 connect_timeout

 #定义重试次数

 nb_get_retry

 delay_before_retry

 }

 }

 real_server 192.168.205.118  {

 weight

 HTTP_GET {

 url {

 path /

 #http返回状态为200, 说明状态ok

 status_code

 }

 #定义超时时间

 connect_timeout

 #定义重试次数

 nb_get_retry

 delay_before_retry

 }

 }

keepalived.conf

C. [root@ha1 keepalived]# scp keepalived.conf ha2:/etc/keepalived/ #拷贝到另一台设备上

D. [root@ha2 ~]# vim /etc/keepalived/keepalived.conf #修改ha2上的配置

#配置状态
state BACKUP
#优先级
priority 100

E. [root@steppingstone ~]# ha 'service keepalived start'; echop; done #启动服务
F. [root@steppingstone ~]# ha 'ifconfig'; echop; done #查看网卡状态

G. [root@steppingstone ~]# ha 'ipvsadm -L -n'; echop; done #查看ipvs规则

5. 测试Realserver的切换

A. [root@rs1 ~]# service httpd stop #在一台rs上停止web服务
B. [root@steppingstone ~]# ha 'ipvsadm -L -n'; echop; done

C. 通知邮件

6. failback页面测试

A. [root@steppingstone ~]# ha 'yum install httpd -y; echo "<h1>`uname -n`, RealServer is rairing!</h1>">/www/html/index.html; service httpd start'; echop; done
B. 测试

a. [root@steppingstone ~]# rs 'service httpd stop'; echop; done #停掉realserver
b. [root@steppingstone ~]# ha 'ipvsadm -L -n'; echop; done

c. [root@rs1 ~]# service httpd start

d. [root@steppingstone ~]# ha 'ipvsadm -L -n'; echop; done

7. keepalived自动切换

A. [root@ha1 ~]# touch /etc/keepalived/down #创建文件模拟测试

B. [root@ha1 keepalived]# tail /var/log/messages -f | grep Keepalived #查看日志

8. keepalived切换邮件通告

A. [root@ha1 ~]# vim /etc/keepalived/keepalived_notify.sh #编辑邮件通知脚本, 改文件拷贝到ha2上相同位置

#!/bin/bash

#指定要接收的邮件的联系人

contact=xxxxxx@163.com

#命令帮助函数

Usage() {

echo "Usage: `basename $0` {master|backup|fault} VIP"

}

#发送邮件函数

Notify() {

subject="`hostname`s status changed to $1"

mailbody="`date "+%F %T"`: `hostname`'s status change to $1, $VIP floating."

echo $mailbody | mail -s "$subject" -r xxxxxx@163.com $contact

}

#判断命令使用是否正确

[ $# -lt 2 ] && Usage && exit

#接收到vip地址

VIP=$2

#判断主题

case $1 in

master)

Notify master

;;

backup)

Notify backup

;;

fault)

Notify fault

;;

*)

Usage

exit 1

;;

esac

B. [root@ha1 ~]# vim /etc/keepalived/keepalived.conf #查看配置文件

vrrp_instance VI_1 {
#定义keepalived节点转换通知
notify_master "/etc/keepalived/keepalived_notify.sh master 192.168.205.80"
notify_backup "/etc/keepalived/keepalived_notify.sh backup 192.168.205.80"
notify_fault "/etc/keepalived/keepalived_notify.sh fault 192.168.205.80"
}

C. 通知邮件