HA Cluster的目的，为了防止重要的服务器在提供服务时，出现不可抗力的因素，例如硬件故障
自然灾害，断电，软件bug，操作系统bug等，导致提供服务的主机出现宕机，死机，从而影响正
常业务，因此采用高可用的方案，实现持续性稳定的提供主机服务的方案称为HA
A=可用
MTBF=平均无故障时间
MTTR=平均修复时长
换算公式
A=MTBF/(MTBF+MTTR)
注意提升A值的方法：
1.分子足够大，但是不划算，成本太高
2.降低分母，即降低平均修复时长，成本较低效果出色
如何降低平均修复时长？
建立备用服务器，实现Failover功能。
原理：在主服务器发生故障时，快速转移IP地址（floating ip），以及快速转移应用程序至备用服务器
需要相关软件转移IP（转移IP即实现ip地址从新配置），转移服务（即在备用主机上启动相关服务应用程序）
总体来说HA 即为在主服务器宕机时，实现备用服务器的快速切换
关键点：IP地址转移，数据共享
HA Cluster （ip，nginx）ip与nginx进程通常称为HA资源
备用服务器使用“心跳”检测，向主服务器发起udp报文（UDP报文不需要三次握手等),
根据主服务器的响应来判断主服务器是否正常工作
关键点：响应时间，资源争用共享存储
假如链接主从服务器的网线连接中断，则会导致，ip争夺，而且最主要的是存储的混乱（同一文件
一边在增加，另一边再删除）
会导致源数据的损坏，损害很大，解决方法，使用爆头设备（STONITH），在补刀，将未彻底断电的还在运行设备断电
当处理完主服务器的故障后，还要将服务器上线，即为Failback
Failover<------->Failback
HA Cluster实现方案
1、vrrp协议的实现
keepalived
2、ais（available Interface standard）：可用接口标准，完备HA集群
RHCS（cmam）
heartbeat
corosync
Keepalived：
vrrp协议：Virtual Redundant Protocol
术语:
虚拟路由：virtual router
虚拟路由器标识：VRID（0-255）
物理路由：
master：主设备
back：备用设备
priority：优先级
VIP：virtual Ip
VMAC:Virtual MAC (00-00-5e-00-01-VRID)
GraciousARP(免费arp)
通告：心跳，优先级等；周期性；
抢占式，非抢占式；
安全工作：
认证：
无认证
简单字符认证
MD5
工作模式
主/备：单虚拟路由器；
主/主：主/备（虚拟路由器1），备/主（虚拟路径器2）
特点：
vrrp协议的软件实现，原生设计的目的为了高可用ipvs服务：
vrrp协议完成地址流动；
为vip地址所在的节点生成ipvs规则（在配置文件中预先定义）；
为ipvs集群的各RS做健康状态检测；
基于脚本调用接口通过执行脚本完成脚本中定义的功能，进而影响集群事务；
组件：
核心组件：
vrrp stack
ipvs wrapper
checkers
控制组件：配置文件分析器
IO复用器
内存管理组件
HA Cluster的配置前提：
（1）各节点时间必须同步
（2）确保iptables及selinux不会成为阻碍；
（3）各节点之间可通过主机名互相通信(对KA并非必须)；
建议使用/etc/hosts文件实现；
（4）各节点之间的root用户可以基于密钥认证的ssh服务完成互相通信（并非必须）
keepalived安装配置：
CentOS 6.4+随base仓库提供；
1、同步时间
配置chronyd服务器172.18。200.100
yum安装chrony，并启动服务
[root@localhost ~]# service chronyd start
Starting chronyd: [ OK ]
使用ntpdate命令，同步172.18.10.10以及172.18.10.11的时间
[root@localhost ~]# ntpdate 172.18.200.100
2、清空iptables和selinux
iptables -F
setenforce 0
3、配置hosts文件（非必须）
4、安装keepalived
[root@localhost ~]# yum install keepalived
[root@localhost ~]# cd /etc/keepalived/
[root@localhost keepalived]# ls
keepalived.conf
[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak
[root@localhost keepalived]# ls
keepalived.conf keepalived.conf.bak
[root@localhost keepalived]# vim keepalived.conf
主配置文件：/etc/keepalived/keepalived.conf
配置文件组成部分及相关选项解释
TOP HIERACHY
GLOBAL CONFIGURATION
Global definitions
Static routes/addresses
VRRPD CONFIGURATION
VRRP synchronization group(s)：vrrp同步组；
VRRP instance(s)：每个vrrp instance即一个vrrp路由器；
LVS CONFIGURATION
Virtual server group(s)
Virtual server(s)：ipvs集群的vs和rs；
global_defs { ###全局定义
notification_email {
acassen@firewall.loc
failover@firewall.loc ####定义出现问题后发送邮箱的地址
sysadmin@firewall.loc
}
notification_email_from Alexandre.Cassen@firewall.loc ##从哪里发过来
smtp_server 192.168.200.1 ###邮件服务器地址
smtp_connect_timeout 30#####超时时间
router_id LVS_DEVEL###路由器IP
vrrp_mcast_group4 224.0.100.5###ipv4多播地址
}
vrrp_instance VI_1 { ##vrrp配置段
state MASTER###表示是主还是从这里显示主，另一个则为从
interface eth0###表明工作从哪个网卡发出 “多波心跳信息”
virtual_router_id 51###虚拟路由ID
priority 100###主的优先级
advert_int 1 ##通告时间间隔
authentication###认证
auth_type PASS####认证类型：简单密钥认证
auth_pass 1111#####认证密码：最多不能超过8位
}
virtual_ipaddress {##虚拟IP地址配在哪个网卡上
192.168.200.16/24 dev eth0 ##定义配置在哪个网卡的别名上
192.168.200.17
192.168.200.18
}
}
track_interface { ##配置要监控的网络接口，一旦接口出现故障，则转为FAULT状态；即接口跟踪
eth0
eth2
...
}
nopreempt：定义工作模式为非抢占模式；
preempt_delay 300：抢占式模式下，节点上线后触发新选举操作的延迟时长；
5、修改配置文件
[root@localhost keepalived]# vim keepalived.conf
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node1
vrrp_mcast_group4 224.0.100.50
}
vrrp_instance myroute {
state MASTER
interface eth2
virtual_router_id 50
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
172.18.50.50/16 dev eth2
}
}
6、将配置文件发送到另一台机器10上
[root@localhost keepalived]# scp keepalived.conf 172.18.10.10:/etc/keepalived/
修改配置文件
[root@localhost keepalived]# vim keepalived.conf
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node2
vrrp_mcast_group4 224.0.100.50
}
vrrp_instance myroute {
state BACKUP
interface eth2
virtual_router_id 50
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
172.18.50.50/16 dev eth2
}
}
7、启动服务
启动备用服务器11
[root@localhost ~]# service keepalived start
查看地址
[root@localhost ~]# ip a
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth2:
link/ether 00:0c:29:07:27:ff brd ff:ff:ff:ff:ff:ff
inet 172.18.10.10/16 brd 172.18.255.255 scope global eth2
inet 172.18.50.50/16 scope global secondary eth2
inet6 fe80::20c:29ff:fe07:27ff/64 scope link
valid_lft forever preferred_lft forever
发现地址已经添加，这是若开启主服务器，由于没有设置抢断延迟，则会立刻抢断
8、启动主服务器
[root@localhost keepalived]# service keepalived start
Starting keepalived: [ OK ]
[root@localhost keepalived]# ip a
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth2:
link/ether 00:0c:29:99:76:84 brd ff:ff:ff:ff:ff:ff
inet 172.18.10.11/16 brd 172.18.255.255 scope global eth2
inet 172.18.50.50/16 scope global secondary eth2
inet6 fe80::20c:29ff:fe99:7684/64 scope link
valid_lft forever preferred_lft forever
发现地址已经添加
而从服务器11上
[root@localhost ~]# ip a
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth2:
link/ether 00:0c:29:07:27:ff brd ff:ff:ff:ff:ff:ff
inet 172.18.10.10/16 brd 172.18.255.255 scope global eth2
inet6 fe80::20c:29ff:fe07:27ff/64 scope link
valid_lft forever preferred_lft forever
IP地址已经删除
9、使用tcpdump抓包工具查看主从服务器的相应心跳测试
[root@localhost keepalived]# tcpdump -i eth2 host 224.0.100.50 ###在主服务器端抓包
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
16:39:33.357307 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:34.358905 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:35.360605 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:36.362301 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:37.363904 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:38.365658 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:39.367266 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:40.368921 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:41.370599 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
[root@localhost ~]# tcpdump -i eth2 -nn host 224.0.100.50 ###在从服务器端抓包
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
16:39:40.367044 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:41.368741 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:42.370289 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:43.371983 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:44.373750 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:45.375413 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:46.377092 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
16:39:47.378760 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
分析说明。实现简单的vrrp
即从服务器每隔一秒向主服务器发送1个通报报文。探测主服务器是否存活，实现具体实施软件keepalived
###############################################################################################################################
双主模型
1、我们在172.18.10.11上配置了主服务器配置，双主服务可在配置文件下面继续添如下内容，配置如下
[root@localhost keepalived]# vim keepalived.conf
vrrp_instance myroute2 {
state BACKUP
interface eth2
virtual_router_id 51
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass 123457
}
virtual_ipaddress {
172.18.51.51/16 dev eth2
}
}
2、将内容服务至粘贴至172.18.10.10服务器的keepalived.conf配置文件中,然后需要在state和priority上进行相应修改
vrrp_instance myroute2 {
state MASTER
interface eth2
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 123457
}
virtual_ipaddress {
172.18.51.51/16 dev eth2
}
}
保存并退出，实现双主模型的设置
3、从启服务并测试
service keepalived restart
Stopping keepalived: [ OK ]
Starting keepalived: [ OK ]
使用tcpdump抓包，结果如下
172.18.10.11端
[root@localhost keepalived]# tcpdump -i eth2 -nn host 224.0.100.50
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
00:50:20.150330 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:50:20.521639 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
00:50:21.151175 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:50:21.522539 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
00:50:22.152517 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:50:22.523232 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
00:50:23.154334 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:50:23.524046 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
172.18.10.10端
[root@localhost keepalived]# tcpdump -i eth2 host 224.0.100.50
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
00:54:01.436075 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:54:01.437266 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
00:54:02.437295 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:54:02.438831 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
00:54:03.438695 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:54:03.439205 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
分析每次都会收到两次信息，一次发送，一次接收
使用iptable设置规则，拒绝172.18.10.11向224.0.100.50发送通知报文
[root@localhost keepalived]# iptables -A OUTPUT -s 172.18.10.11 -d 224.0.100.50 -j REJECT
在172.18.10.10端使用tcpdump抓包
[root@localhost keepalived]# tcpdump -i eth2 -nn host 224.0.100.50
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes
00:50:20.150330 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:50:20.521639 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
00:50:21.151175 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:50:21.522539 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
00:50:22.152517 IP 172.18.10.10 > 224.0.100.50: VRRPv2, Advertisement, vrid 51, prio 100, authtype simple, intvl 1s, length 20
00:50:22.523232 IP 172.18.10.11 > 224.0.100.50: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
分析发现发送两条通告，因为172.18.10.11不通告，便认为172.18.10.11挂掉了，因此抢断，让自己变为主机。即别人不通告则认为对方挂掉了
可以使用ip a l 查看相应的ip地址获取：
[root@localhost keepalived]# ip a l
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth2:
link/ether 00:0c:29:07:27:ff brd ff:ff:ff:ff:ff:ff
inet 172.18.10.10/16 brd 172.18.255.255 scope global eth2
inet 172.18.51.51/16 scope global secondary eth2
inet 172.18.50.50/16 scope global secondary eth2
inet6 fe80::20c:29ff:fe07:27ff/64 scope link
valid_lft forever preferred_lft forever
再次在172.18.10.11服务器上，清空iptables规则
[root@localhost keepalived]# iptables -F
再回到172.18.10.10服务器上使用ip a l 查询
[root@localhost keepalived]# ip a l
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth2:
link/ether 00:0c:29:07:27:ff brd ff:ff:ff:ff:ff:ff
inet 172.18.10.10/16 brd 172.18.255.255 scope global eth2
inet 172.18.51.51/16 scope global secondary eth2
inet6 fe80::20c:29ff:fe07:27ff/64 scope link
valid_lft forever preferred_lft forever
发现地址已经立马被夺回，是因为工作在抢占模式下。没有设置preempt_delay 300抢占延迟时间，
结论：实现双主模型实验
##################################################################################################################
如何实现自定义通知脚本
一、在172.18.10.11服务器上添加脚本，实现自动发邮件
1.编写邮件脚本
vim notify.sh
#!/bin/bash
#
contact='root@localhost'
notify() {
mailsubject="vrrp： $(hostname) to be $1"
mailbody="$(hostname) to be $1,vrrp transition, $(date)."
echo "$mailbody" | mail -s "$mailsubject" $contact
}
case $1 in
master)
notify master ;;
backup)
notify backup ;;
fault)
notify fault ;;
*)
echo "Usage: $(basename $0 ) master|backup|fault"
exit 1
;;
esac
2、测试脚本
语法检测
[root@localhost keepalived]# bash -n notify.sh
运行脚本测试
[root@localhost keepalived]# bash -x notify.sh master
+ contact=root@localhost
+ case $1 in
+ notify master
++ hostname
+ mailsubject='localhost.localdomain to be master'
++ hostname
++ date
+ mailbody='localhost.localdomain to be master,vrrp transition, Mon May 15 01:36:33 CST 2017.'
+ echo 'localhost.localdomain to be master,vrrp transition, Mon May 15 01:36:33 CST 2017.'
+ mail -s mailsubject root@localhost
[root@localhost keepalived]# vim notify.sh
You have mail in /var/spool/mail/root
3、查看收到的邮件
[root@localhost keepalived]# mail
Heirloom Mail version 12.4 7/29/08. Type ? for help.
"/var/spool/mail/root": 1 message 1 new
>N 1 root Mon May 15 01:36 18/696 "mailsubject"
&
Message 1:
From root@localhost.localdomain Mon May 15 01:36:34 2017
Return-Path:
X-Original-To: root@localhost
Delivered-To: root@localhost.localdomain
Date: Mon, 15 May 2017 01:36:33 +0800
To: root@localhost.localdomain
Subject: mailsubject
User-Agent: Heirloom mailx 12.4 7/29/08
Content-Type: text/plain; charset=us-ascii
From: root@localhost.localdomain (root)
Status: R
localhost.localdomain to be master,vrrp transition, Mon May 15 01:36:33 CST 2017.
&
4、将脚本发送至172.18.10.10端
[root@localhost keepalived]# scp notify.sh 172.18.10.10:/etc/keepalived/
root@172.18.10.10's password:
notify.sh 100% 367 0.4KB/s 00:00
5、调用脚本
[root@localhost keepalived]# vim keepalived.conf
在172.18.10.11上的vrrp_instance myrouter1下面添加如下内容,注意是放在vrrp_instance myrouter1上下文中调用
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
在172.18.10.10上的vrrp_instance myrouter2下面添加如下内容
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
6，为了实现测试效果，将之前定义的双主模型删除，并停止服务（在10.10和10.11上做同样的操作）
：.,$d 表示从当前行都最后一行全部删除
[root@localhost keepalived]# service keepalived stop
Stopping keepalived: [ OK ]
7、给之前编写的脚本加上执行权限
[root@localhost keepalived]# chmod +x notify.sh
[root@localhost keepalived]# ll
total 8
-rw-r--r-- 1 root root 658 May 15 02:01 keepalived.conf
-rwxr-xr-x 1 root root 367 May 15 01:41 notify.sh
8、启动服务
在172.18.10.11端
[root@localhost keepalived]# service keepalived start
Starting keepalived: [ OK ]
[root@localhost keepalived]# ip a l
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth2:
link/ether 00:0c:29:99:76:84 brd ff:ff:ff:ff:ff:ff
inet 172.18.10.11/16 brd 172.18.255.255 scope global eth2
inet 172.18.50.50/16 scope global secondary eth2
inet6 fe80::20c:29ff:fe99:7684/64 scope link
valid_lft forever preferred_lft forever
[root@localhost keepalived]# mail
Heirloom Mail version 12.4 7/29/08. Type ? for help.
"/var/spool/mail/root": 3 messages 2 unread
1 root Mon May 15 01:36 19/707 "mailsubject"
>U 2 root Mon May 15 11:03 19/735 "vrrp: localhost.localdomain to be master"
&
9、启动172.18.10.10端的keepalived，并且再次到172.18.10.11端查看邮件
[root@localhost ~]# mail
Heirloom Mail version 12.4 7/29/08. Type ? for help.
"/var/spool/mail/root": 7 messages 5 new 7 unread
U 1 root Mon May 15 11:09 19/735 "vrrp: localhost.localdomain to be backup"
U 2 root Mon May 15 11:11 19/735 "vrrp: localhost.localdomain to be backup"
>N 3 root Mon May 15 11:11 18/725 "vrrp: localhost.localdomain to be master"
N 4 root Mon May 15 11:11 18/725 "vrrp: localhost.localdomain to be backup"
N 5 root Mon May 15 11:26 18/725 "vrrp: localhost.localdomain to be backup"
N 6 root Mon May 15 11:26 18/725 "vrrp: localhost.localdomain to be master"
N 7 root Mon May 15 11:26 18/725 "vrrp: localhost.localdomain to be backup"
&
结论：通知脚本功能实现
######################################################################################################
如何实现 keepalived 高可用LVS （重点）
实验准备：4台虚拟主机
其中172.18.10.10和172.18.10.11做为VS端分别为VS2和VS1
172.18.200.100和172.18.249.57做为RS分别为RS1和RS2
首先分别再RS1和RS2端安装httpd
1、进行如下配置
[root@localhost ~]# cat /var/www/html/index.html
[root@localhost ~]# cat /var/www/html/index.html
2、编写VIP配置脚本
vim setparam.sh
#!/bin/bash
#
vip='172.18.50.50'
netmask='255.255.255.255'
iface='lo:0'
case $1 in
start)
echo 1 > /pro/sys/net/ipv4/conf/all/arp_ignore
echo 1 > /pro/sys/net/ipv4/conf/lo/arp_ignore
echo 2 > /pro/sys/net/ipv4/conf/all/arp_ignore
echo 2 > /pro/sys/net/ipv4/conf/lo/arp_ignore
ifconfig $iface $vip netmask $netmask broadcast $vip up
route add -host $vip dev $iface
;;
stop)
ifconfig $iface down
echo 0 > /pro/sys/net/ipv4/conf/all/arp_ignore
echo 0 > /pro/sys/net/ipv4/conf/lo/arp_ignore
echo 0 > /pro/sys/net/ipv4/conf/all/arp_ignore
echo 0 > /pro/sys/net/ipv4/conf/lo/arp_ignore
;;
esac
3、测试脚本
[root@localhost ~]# bash -n setparam.sh
[root@localhost ~]# bash -x setparam.sh start
+ vip=172.18.50.50
+ netmask=255.255.255.255
+ iface=lo:0
+ case $1 in
+ echo 1
setparam.sh: line 9: /pro/sys/net/ipv4/conf/all/arp_ignore: No such file or directory
+ echo 1
setparam.sh: line 10: /pro/sys/net/ipv4/conf/lo/arp_ignore: No such file or directory
+ echo 2
setparam.sh: line 11: /pro/sys/net/ipv4/conf/all/arp_announce: No such file or directory
+ echo 2
setparam.sh: line 12: /pro/sys/net/ipv4/conf/lo/arp_announce: No such file or directory
+ ifconfig lo:0 172.18.50.50 netmask 255.255.255.255 broadcast 172.18.50.50 up
+ route add -host 172.18.50.50 dev lo:0
4、使用scp将脚本分发至RS2
[root@localhost ~]# scp setparam.sh 172.18.249.57:/root
root@172.18.249.57's password:
setparam.sh 100% 610 0.6KB/s 00:00
5、在RS2端执行脚本，并查看是否生成VIP
[root@localhost ~]# bash -x setparam.sh start
+ vip=172.18.50.50
+ netmask=255.255.255.255
+ iface=lo:0
+ case $1 in
+ echo 1
setparam.sh: line 9: /pro/sys/net/ipv4/conf/all/arp_ignore: No such file or directory
+ echo 1
setparam.sh: line 10: /pro/sys/net/ipv4/conf/lo/arp_ignore: No such file or directory
+ echo 2
setparam.sh: line 11: /pro/sys/net/ipv4/conf/all/arp_announce: No such file or directory
+ echo 2
setparam.sh: line 12: /pro/sys/net/ipv4/conf/lo/arp_announce: No such file or directory
+ ifconfig lo:0 172.18.50.50 netmask 255.255.255.255 broadcast 172.18.50.50 up
+ route add -host 172.18.50.50 dev lo:0
[root@localhost ~]# ip a
1: lo:
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet 172.18.50.50/32 brd 172.18.50.50 scope global lo:0
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0:
link/ether 00:0c:29:b2:ca:ea brd ff:ff:ff:ff:ff:ff
inet 172.18.249.57/16 brd 172.18.255.255 scope global eth0
inet6 fe80::20c:29ff:feb2:caea/64 scope link
valid_lft forever preferred_lft forever
6、启动RS1和RS2的httpd服务，并查看端口，两端都要查看，这里只演示一端的
[root@localhost ~]# service httpd start
[root@localhost ~]# ss -tnl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 :::80 :::*
LISTEN 0 128 :::22 :::*
LISTEN 0 128 *:22 *:*
LISTEN 0 100 ::1:25 :::*
LISTEN 0 100 127.0.0.1:25
7、在两个前段节点生成ipvs规则
在VS2端
停止keepalived服务
配置sorry server页面
vim /var/www/html/index.html
Director2 sorry server2
启动httpd服务
[root@localhost ~]# service httpd start
在VS1端
首先停止keepalived服务
[root@localhost ~]# service keepalived stop
vim /var/www/html/index.html
Director1
启动httpd服务
[root@localhost ~]# service httpd start
在VS1端编辑keepalived配置文件，添加如下内容：
virtual_server 172.18.50.50 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 0
protocol TCP
real_server 172.18.10.11 80 {
weight 1
HTTP_GET {
persistence_timeout 0
protocol TCP
sorry_server 127.0.0.1 80
real_server 172.18.10.11 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.10.10 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
在VS2端，同样编辑keepalived.conf文件，添加如下内容
virtual_server 172.18.50.50 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 0
protocol TCP
sorry_server 127.0.0.1 80
real_server 172.18.10.11 80 {
weight 1
HTTP_GET {
persistence_timeout 0
protocol TCP
real_server 172.18.10.11 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.10.10 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
在VS2上启动keepalived服务
[root@localhost ~]# service keepalived start
Starting keepalived: [ OK ]
[root@localhost ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.18.50.50:80 wrr
-> 172.18.200.100:80 Route 1 0 0
-> 172.18.249.57:80 Route 1 0 0
在客户端使用curl进行访问测试（配置完有一定延迟，稍等片刻在访问）
[root@localhost ~]# curl http://172.18.50.50
[root@localhost ~]# curl http://172.18.50.50
[root@localhost ~]# curl http://172.18.50.50
[root@localhost ~]# curl http://172.18.50.50
[root@localhost ~]# curl http://172.18.50.50
[root@localhost ~]# curl http://172.18.50.50
[root@localhost ~]# curl http://172.18.50.50
[root@localhost ~]# curl http://172.18.50.50
在172.18.200.100端停止httpd服务
[root@localhost ~]# service httpd stop
Stopping httpd: [ OK ]
在VS2端使用ipvsadm观察
[root@localhost keepalived]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.18.50.50:80 wrr
-> 172.18.249.57:80 Route 1 0 2
在172.18.200.100端停止httpd服务
[root@localhost ~]# service httpd start
在VS2端使用ipvsadm观察
[root@localhost keepalived]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.18.50.50:80 wrr
-> 172.18.200.100:80 Route 1 0 0
-> 172.18.249.57:80 Route 1 0 0
启动VS1上的keepalived服务，并且关闭VS2，客户端使用curl测试发现，仍然能够访问
[root@localhost keepalived]# curl http://172.18.50.50
[root@localhost keepalived]# curl http://172.18.50.50
[root@localhost keepalived]# curl http://172.18.50.50
[root@localhost keepalived]# curl http://172.18.50.50
更改配置文件，将之前删除的双主内容添加进去
VS1端
vrrp_instance myroute2 {
state BACKUP
interface eth2
virtual_router_id 51
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass 123457
}
virtual_ipaddress {
172.18.51.51/16 dev eth2
}
}
VS2端
vrrp_instance myroute2 {
state MASTER
interface eth2
virtual_router_id 51
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass 123457
}
virtual_ipaddress {
172.18.51.51/16 dev eth2
}
}
重启keepalived服务,相当重要，，，，，不重启不会有效果，这就是个坑
总结VS端
VS2端keepalived配置
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node2
vrrp_mcast_group4 224.0.100.50
}
vrrp_instance myroute1 {
state BACKUP
interface eth2
virtual_router_id 50
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
172.18.50.50/16 dev eth2
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance myroute2 {
state MASTER
interface eth2
virtual_router_id 51
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass 123457
}
virtual_ipaddress {
172.18.51.51/16 dev eth2
}
}
virtual_server 172.18.50.50 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 0
protocol TCP
sorry_server 127.0.0.1 80
real_server 172.18.200.100 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.249.57 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
virtual_server 172.18.51.51 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 0
protocol TCP
sorry_server 127.0.0.1 80
real_server 172.18.200.100 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.249.57 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
VS1端keepalived配置
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id node1
vrrp_mcast_group4 224.0.100.50
}
vrrp_instance myroute1 {
state MASTER
interface eth2
virtual_router_id 50
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
172.18.50.50/16 dev eth2
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance myroute2 {
state BACKUP
interface eth2
virtual_router_id 51
priority 98
advert_int 1
authentication {
auth_type PASS
auth_pass 123457
}
virtual_ipaddress {
172.18.51.51/16 dev eth2
}
}
virtual_server 172.18.50.50 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 0
protocol TCP
sorry_server 127.0.0.1 80
real_server 172.18.200.100 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.249.57 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
virtual_server 172.18.51.51 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
persistence_timeout 0
protocol TCP
sorry_server 127.0.0.1 80
real_server 172.18.200.100 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 172.18.249.57 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
VIP配置脚本 （由用户是双主模型因此VIP有两个）
#!/bin/bash
#
vip='172.18.50.50'
vip2='172.18.51.51'
netmask='255.255.255.255'
iface='lo:0'
iface2='lo:1'
case $1 in
start)
echo 1 > /pro/sys/net/ipv4/conf/all/arp_ignore
echo 1 > /pro/sys/net/ipv4/conf/lo/arp_ignore
echo 2 > /pro/sys/net/ipv4/conf/all/arp_announce
echo 2 > /pro/sys/net/ipv4/conf/lo/arp_announce
ifconfig $iface $vip netmask $netmask broadcast $vip up
ifconfig $iface2 $vip2 netmask $netmask broadcast $vip2 up
route add -host $vip dev $iface
;;
stop)
ifconfig $iface down
ifconfig $iface2 down
echo 0 > /pro/sys/net/ipv4/conf/all/arp_ignore
echo 0 > /pro/sys/net/ipv4/conf/lo/arp_ignore
echo 0 > /pro/sys/net/ipv4/conf/all/arp_announce
echo 0 > /pro/sys/net/ipv4/conf/lo/arp_announce
;;
esac
实验结论：实现keepalived 高可用lvs负载均衡
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