Linux 高可用（HA）集羣之keepalived詳解

時間 2021-01-19

標籤 html 前端 node vim 後端 centos 安全 bash 服務器網絡欄目 Linux 简体版

原文原文鏈接

大綱html

1、前言前端

2、Keepalived 詳解node

3、環境準備vim

4、LVS+Keepalived 實現高可用的前端負載均衡器後端

1、前言centos

這篇文章是前幾篇文章的總結，咱們先簡單的總結一下咱們前面講解的內容，前面咱們講解了，LVS（負載均衡器）、Heartbeat、Corosync、Pacemaker、Web高可用集羣、MySQL高可用集羣、DRDB、iscsi、gfs二、cLVM等，惟一沒有講解的就是LVS可用，也就是前端高可用，咱們這一篇博文主要講解內容。在說這個以前咱們得和你們討論一個問題，也是好多博友問的問題。Heartbeat、Corosync、Keepalived這三個集羣組件咱們到底選哪一個好，首先我想說明的是，Heartbeat、Corosync是屬於同一類型，Keepalived與Heartbeat、Corosync，根本不是同一類型的。Keepalived使用的vrrp協議方式，虛擬路由冗餘協議 (Virtual Router Redundancy Protocol，簡稱VRRP)；Heartbeat或Corosync是基於主機或網絡服務的高可用方式；簡單的說就是，Keepalived的目的是模擬路由器的高可用，Heartbeat或Corosync的目的是實現Service的高可用。因此通常Keepalived是實現前端高可用，經常使用的前端高可用的組合有，就是咱們常見的LVS+Keepalived、Nginx+Keepalived、HAproxy+Keepalived。而Heartbeat或Corosync是實現服務的高可用，常見的組合有Heartbeat v3(Corosync)+Pacemaker+NFS+Httpd 實現Web服務器的高可用、Heartbeat v3(Corosync)+Pacemaker+NFS+MySQL 實現MySQL服務器的高可用。總結一下，Keepalived中實現輕量級的高可用，通常用於前端高可用，且不須要共享存儲，通常經常使用於兩個節點的高可用。而Heartbeat(或Corosync)通常用於服務的高可用，且須要共享存儲，通常用於多節點的高可用。這個問題咱們說明白了，又有博友會問了，那heartbaet與corosync咱們又應該選擇哪一個好啊，我想說咱們通常用corosync，由於corosync的運行機制更優於heartbeat，就連從heartbeat分離出來的pacemaker都說在之後的開發當中更傾向於corosync，因此如今corosync+pacemaker是最佳組合。但說實話我對於軟件沒有任何傾向性，因此我把全部的集羣軟件都和你們說了一下，我認爲無論什麼軟件，只要它能存活下來都有它的特色和應用領域，只有把特定的軟件放在特定的位置才能發揮最大的做用，那首先咱們得對這個軟件有全部瞭解。學習一種軟件的最好方法，就是去查官方文檔。好了說了那麼多但願你們有所收穫，下面咱們來講一說keepalived。安全

2、Keepalived 詳解bash

1.Keepalived 定義服務器

Keepalived 是一個基於VRRP協議來實現的LVS服務高可用方案，能夠利用其來避免單點故障。一個LVS服務會有2臺服務器運行Keepalived，一臺爲主服務器（MASTER），一臺爲備份服務器（BACKUP），可是對外表現爲一個虛擬IP，主服務器會發送特定的消息給備份服務器，當備份服務器收不到這個消息的時候，即主服務器宕機的時候，備份服務器就會接管虛擬IP，繼續提供服務，從而保證了高可用性。Keepalived是VRRP的完美實現，所以在介紹keepalived以前，先介紹一下VRRP的原理。網絡

2.VRRP 協議簡介

在現實的網絡環境中，兩臺須要通訊的主機大多數狀況下並無直接的物理鏈接。對於這樣的狀況，它們之間路由怎樣選擇？主機如何選定到達目的主機的下一跳路由，這個問題一般的解決方法有二種：

在主機上使用動態路由協議(RIP、OSPF等)
在主機上配置靜態路由

很明顯，在主機上配置動態路由是很是不切實際的，由於管理、維護成本以及是否支持等諸多問題。配置靜態路由就變得十分流行，但路由器(或者說默認網關default gateway)卻常常成爲單點故障。VRRP的目的就是爲了解決靜態路由單點故障問題，VRRP經過一競選(election)協議來動態的將路由任務交給LAN中虛擬路由器中的某臺VRRP路由器。

3.VRRP 工做機制

在一個VRRP虛擬路由器中，有多臺物理的VRRP路由器，可是這多臺的物理的機器並不能同時工做，而是由一臺稱爲MASTER的負責路由工做，其它的都是BACKUP，MASTER並不是一成不變，VRRP讓每一個VRRP路由器參與競選，最終獲勝的就是MASTER。MASTER擁有一些特權，好比，擁有虛擬路由器的IP地址，咱們的主機就是用這個IP地址做爲靜態路由的。擁有特權的MASTER要負責轉發發送給網關地址的包和響應ARP請求。

VRRP經過競選協議來實現虛擬路由器的功能，全部的協議報文都是經過IP多播(multicast)包(多播地址224.0.0.18)形式發送的。虛擬路由器由VRID(範圍0-255)和一組IP地址組成，對外表現爲一個周知的MAC地址。因此，在一個虛擬路由器中，無論誰是MASTER，對外都是相同的MAC和IP(稱之爲VIP)。客戶端主機並不須要由於MASTER的改變而修改本身的路由配置，對客戶端來講，這種主從的切換是透明的。

在一個虛擬路由器中，只有做爲MASTER的VRRP路由器會一直髮送VRRP通告信息(VRRPAdvertisement message)，BACKUP不會搶佔MASTER，除非它的優先級(priority)更高。當MASTER不可用時(BACKUP收不到通告信息)，多臺BACKUP中優先級最高的這臺會被搶佔爲MASTER。這種搶佔是很是快速的(<1s)，以保證服務的連續性。因爲安全性考慮，VRRP包使用了加密協議進行加密。

4.VRRP 工做流程

(1).初始化：
路由器啓動時，若是路由器的優先級是255(最高優先級，路由器擁有路由器地址)，要發送VRRP通告信息，併發送廣播ARP信息通告路由器IP地址對應的MAC地址爲路由虛擬MAC，設置通告信息定時器準備定時發送VRRP通告信息，轉爲MASTER狀態；不然進入BACKUP狀態，設置定時器檢查定時檢查是否收到MASTER的通告信息。

(2).Master

設置定時通告定時器；
用VRRP虛擬MAC地址響應路由器IP地址的ARP請求；
轉發目的MAC是VRRP虛擬MAC的數據包；
若是是虛擬路由器IP的擁有者，將接受目的地址是虛擬路由器IP的數據包，不然丟棄；
當收到shutdown的事件時刪除定時通告定時器，發送優先權級爲0的通告包，轉初始化狀態；
若是定時通告定時器超時時，發送VRRP通告信息；
收到VRRP通告信息時，若是優先權爲0，發送VRRP通告信息；不然判斷數據的優先級是否高於本機，或相等並且實際IP地址大於本地實際IP，設置定時通告定時器，復位主機超時定時器，轉BACKUP狀態；不然的話，丟棄該通告包；

(3).Backup

設置主機超時定時器；
不能響應針對虛擬路由器IP的ARP請求信息；
丟棄全部目的MAC地址是虛擬路由器MAC地址的數據包；
不接受目的是虛擬路由器IP的全部數據包；
當收到shutdown的事件時刪除主機超時定時器，轉初始化狀態；
主機超時定時器超時的時候，發送VRRP通告信息，廣播ARP地址信息，轉MASTER狀態；
收到VRRP通告信息時，若是優先權爲0，表示進入MASTER選舉；不然判斷數據的優先級是否高於本機，若是高的話認可MASTER有效，復位主機超時定時器；不然的話，丟棄該通告包；

5.ARP查詢處理

當內部主機經過ARP查詢虛擬路由器IP地址對應的MAC地址時，MASTER路由器回覆的MAC地址爲虛擬的VRRP的MAC地址，而不是實際網卡的 MAC地址，這樣在路由器切換時讓內網機器覺察不到；而在路由器從新啓動時，不能主動發送本機網卡的實際MAC地址。若是虛擬路由器開啓的ARP代理 (proxy_arp)功能，代理的ARP迴應也迴應VRRP虛擬MAC地址；好了VRRP的簡單講解就到這裏，咱們下來說解一下Keepalived的案例。

3、環境準備

1.操做系統

CentOS 6.4 X86_64

2.軟件版本

ipvsadm.x86_64 0:1.25-10.el6
keepalived.x86_64 0:1.2.7-3.el6
httpd-2.2.15-29.el6.centos.x86_64

3.實驗拓撲

4.時間同步

node1:

[root@node1 ~]# ntpdate 202.120.2.101

node2:

[root@node2 ~]# ntpdate 202.120.2.101

master:

[root@master ~]# ntpdate 202.120.2.101

slave:

[root@slave ~]# ntpdate 202.120.2.101

5.主機名互相解析

node1:

[root@node1 ~]# cat /etc/hosts  
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4   
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6   
192.168.18.201    node1.test.com    node1   
192.168.18.202    node2.test.com    node2

node2:

[root@node2 ~]# cat /etc/hosts  
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4   
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6   
192.168.18.201    node1.test.com    node1   
192.168.18.202    node2.test.com    node2

6.安裝yum源

node1:

[root@node1 ~]# rpm -ivh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
[root@node1 ~]# rpm -ivh http://elrepo.org/elrepo-release-6-5.el6.elrepo.noarch.rpm

node2:

[root@node2 ~]# rpm -ivh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
[root@node2 ~]# rpm -ivh http://elrepo.org/elrepo-release-6-5.el6.elrepo.noarch.rpm

master:

[root@master ~]# rpm -ivh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
[root@master ~]# rpm -ivh http://elrepo.org/elrepo-release-6-5.el6.elrepo.noarch.rpm

slave:

[root@slave ~]# rpm -ivh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
[root@slave ~]# rpm -ivh http://elrepo.org/elrepo-release-6-5.el6.elrepo.noarch.rpm

4、LVS+Keepalived 實現高可用的前端負載均衡器

node1:

1.安裝httpd

[root@node1 ~]# yum install -y httpd

2.配置httpd

[root@node1 ~]# vim /var/www/html/index.html
<h1>RS1.test.com</h1>

3.啓動httpd

[root@node1 ~]# service httpd start

4.測試

5.設置開機自啓動

[root@node1 ~]# chkconfig httpd on   
[root@node1 ~]# chkconfig httpd --list    
httpd              0:關閉    1:關閉    2:啓用    3:啓用    4:啓用    5:啓用    6:關閉

6.配置node1

[root@node1 ~]# mkdir src   
[root@node1 ~]# cd src/    
[root@node1 src]# vim realserver.sh
#!/bin/bash   
#    
# Script to start LVS DR real server.    
# description: LVS DR real server    
#    
.  /etc/rc.d/init.d/functions
VIP=192.168.18.200 #修改你的VIP   
host=`/bin/hostname`
case "$1" in   
start)    
       # Start LVS-DR real server on this machine.    
        /sbin/ifconfig lo down    
        /sbin/ifconfig lo up    
        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore    
        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce    
        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore    
        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
        /sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up   
        /sbin/route add -host $VIP dev lo:0
;;   
stop)
        # Stop LVS-DR real server loopback device(s).   
        /sbin/ifconfig lo:0 down    
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore    
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce    
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore    
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
;;   
status)
        # Status of LVS-DR real server.   
        islothere=`/sbin/ifconfig lo:0 | grep $VIP`    
        isrothere=`netstat -rn | grep "lo:0" | grep $VIP`    
        if [ ! "$islothere" -o ! "isrothere" ];then    
            # Either the route or the lo:0 device    
            # not found.    
            echo "LVS-DR real server Stopped."    
        else    
            echo "LVS-DR real server Running."    
        fi    
;;    
*)    
            # Invalid entry.    
            echo "$0: Usage: $0 {start|status|stop}"    
            exit 1    
;;    
esac    
[root@node1 src]# chmod +x realserver.sh   
[root@node1 src]# ll    
總用量 4    
-rwxr-xr-x 1 root root 1485 8月  22 10:18 realserver.sh
[root@node1 src]# ./realserver.sh start

7.查看配置

[root@node1 src]# ifconfig   
eth0      Link encap:Ethernet  HWaddr 00:0C:29:11:92:E4 
          inet addr:192.168.18.201  Bcast:192.168.18.255  Mask:255.255.255.0    
          inet6 addr: fe80::20c:29ff:fe11:92e4/64 Scope:Link    
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1    
          RX packets:115061 errors:0 dropped:0 overruns:0 frame:0    
          TX packets:14979 errors:0 dropped:0 overruns:0 carrier:0    
          collisions:0 txqueuelen:1000    
          RX bytes:43448483 (41.4 MiB)  TX bytes:1224926 (1.1 MiB)
lo        Link encap:Local Loopback 
          inet addr:127.0.0.1  Mask:255.0.0.0    
          inet6 addr: ::1/128 Scope:Host    
          UP LOOPBACK RUNNING  MTU:16436  Metric:1    
          RX packets:2 errors:0 dropped:0 overruns:0 frame:0    
          TX packets:2 errors:0 dropped:0 overruns:0 carrier:0    
          collisions:0 txqueuelen:0    
          RX bytes:168 (168.0 b)  TX bytes:168 (168.0 b)
lo:0      Link encap:Local Loopback 
          inet addr:192.168.18.200  Mask:255.255.255.255    
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
[root@node1 src]# route -n   
Kernel IP routing table    
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface    
192.168.18.200  0.0.0.0         255.255.255.255 UH    0      0        0 lo    
192.168.18.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0    
169.254.0.0     0.0.0.0         255.255.0.0     U     1002   0        0 eth0    
0.0.0.0         192.168.18.254  0.0.0.0         UG    0      0        0 eth0
[root@node1 src]# cat /proc/sys/net/ipv4/conf/lo/arp_ignore   
1    
[root@node1 src]# cat /proc/sys/net/ipv4/conf/lo/arp_announce    
2    
[root@node1 src]# cat /proc/sys/net/ipv4/conf/all/arp_ignore    
1    
[root@node1 src]# cat /proc/sys/net/ipv4/conf/all/arp_announce
2

好了，node1到這裏基本配置完成，下面咱們來配置node2。

node2:

1.安裝httpd

[root@node2 ~]# yum install -y httpd

2.配置httpd

[root@node2 ~]# vim /var/www/html/index.html
<h1>RS2.test.com</h1>

3.啓動httpd

[root@node2 ~]# service httpd start

4.測試

5.設置開機自啓動

[root@node2 ~]# chkconfig httpd on   
[root@node2 ~]# chkconfig httpd --list    
httpd              0:關閉    1:關閉    2:啓用    3:啓用    4:啓用    5:啓用    6:關閉

6.配置node2

[root@node2 ~]# mkdir src   
[root@node2 ~]# cd src/    
[root@node2 src]# vim realserver.sh
#!/bin/bash   
#    
# Script to start LVS DR real server.    
# description: LVS DR real server    
#    
.  /etc/rc.d/init.d/functions
VIP=192.168.18.200   
host=`/bin/hostname`
case "$1" in   
start)    
       # Start LVS-DR real server on this machine.    
        /sbin/ifconfig lo down    
        /sbin/ifconfig lo up    
        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore    
        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce    
        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore    
        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
        /sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up   
        /sbin/route add -host $VIP dev lo:0
;;   
stop)
        # Stop LVS-DR real server loopback device(s).   
        /sbin/ifconfig lo:0 down    
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore    
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce    
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore    
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
;;   
status)
        # Status of LVS-DR real server.   
        islothere=`/sbin/ifconfig lo:0 | grep $VIP`    
        isrothere=`netstat -rn | grep "lo:0" | grep $VIP`    
        if [ ! "$islothere" -o ! "isrothere" ];then    
            # Either the route or the lo:0 device    
            # not found.    
            echo "LVS-DR real server Stopped."    
        else    
            echo "LVS-DR real server Running."    
        fi    
;;    
*)    
            # Invalid entry.    
            echo "$0: Usage: $0 {start|status|stop}"    
            exit 1    
;;    
esac
[root@node2 src]# chmod +x realserver.sh   
[root@node2 src]# ./realserver.sh start

7.查看配置

[root@node2 src]# ifconfig   
eth0      Link encap:Ethernet  HWaddr 00:0C:29:B8:DF:6A 
          inet addr:192.168.18.202  Bcast:192.168.18.255  Mask:255.255.255.0    
          inet6 addr: fe80::20c:29ff:feb8:df6a/64 Scope:Link    
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1    
          RX packets:110545 errors:0 dropped:0 overruns:0 frame:0    
          TX packets:10461 errors:0 dropped:0 overruns:0 carrier:0    
          collisions:0 txqueuelen:1000    
          RX bytes:32853789 (31.3 MiB)  TX bytes:889109 (868.2 KiB)
lo        Link encap:Local Loopback 
          inet addr:127.0.0.1  Mask:255.0.0.0    
          inet6 addr: ::1/128 Scope:Host    
          UP LOOPBACK RUNNING  MTU:16436  Metric:1    
          RX packets:6 errors:0 dropped:0 overruns:0 frame:0    
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0    
          collisions:0 txqueuelen:0    
          RX bytes:616 (616.0 b)  TX bytes:616 (616.0 b)
lo:0      Link encap:Local Loopback 
          inet addr:192.168.18.200  Mask:255.255.255.255    
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
[root@node2 src]# route -n   
Kernel IP routing table    
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface    
192.168.18.200  0.0.0.0         255.255.255.255 UH    0      0        0 lo    
192.168.18.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0    
169.254.0.0     0.0.0.0         255.255.0.0     U     1002   0        0 eth0    
0.0.0.0         192.168.18.254  0.0.0.0         UG    0      0        0 eth0
[root@node2 src]# cat /proc/sys/net/ipv4/conf/lo/arp_ignore   
1    
[root@node2 src]# cat /proc/sys/net/ipv4/conf/lo/arp_announce    
2    
[root@node2 src]# cat /proc/sys/net/ipv4/conf/all/arp_ignore    
1    
[root@node2 src]# cat /proc/sys/net/ipv4/conf/all/arp_announce    
2

好了，到這裏node2也基本配置完成。下面咱們來配置master與slave。

masterg與slave:

1.安裝keepalived與ipvsadm

[root@master ~]# yum install -y keepalived ipvsadm
[root@slave ~]# yum install -y keepalived ipvsadm

2.修改配置文件

[root@master ~]# cat /etc/keepalived/keepalived.conf   
! Configuration File for keepalived
global_defs {   
   notification_email {    
15251076067@163.com #配置管理員郵箱    
   }    
   notification_email_from root #配置發件人    
   smtp_server 127.0.0.1 #配置郵件服務器    
   smtp_connect_timeout 30    
   router_id LVS_DEVEL    
}
vrrp_instance VI_1 {   
    state MASTER #配置模式    
    interface eth0    
    virtual_router_id 51    
    priority 101 #配置優先級    
    advert_int 1    
    authentication {    
        auth_type PASS    
        auth_pass 1111    
    }    
    virtual_ipaddress {    
        192.168.18.200 #配置虛擬IP地址    
    }    
}
virtual_server 192.168.18.200 80 {   
    delay_loop 6    
    lb_algo rr    
    lb_kind DR    
    nat_mask 255.255.255.0    
    #persistence_timeout 50    
    protocol TCP
    real_server 192.168.18.201 80 { #配置realaserver   
        weight 1    
        HTTP_GET { #監控配置    
            url {    
              path /    
          status_code 200    
            }    
            connect_timeout 2    
            nb_get_retry 3    
            delay_before_retry 1    
        }    
    }    
    real_server 192.168.18.202 80 {    
        weight 1    
        HTTP_GET {    
            url {    
              path /    
              status_code 200    
            }    
            connect_timeout 2    
            nb_get_retry 3    
            delay_before_retry 1    
        }    
    }    
}

3.將配置文件同步到slave

[root@master ~]# scp /etc/keepalived/keepalived.conf root@192.168.18.207:/etc/keepalived/

4.簡單修改一下slave配置文件

[root@slave keepalived]# cat keepalived.conf   
! Configuration File for keepalived
global_defs {   
   notification_email {    
     15251076067@163.com    
   }    
   notification_email_from root    
   smtp_server 127.0.0.1    
   smtp_connect_timeout 30    
   router_id LVS_DEVEL    
}
vrrp_instance VI_1 {   
    state BACKUP #修改成BACKUP    
    interface eth0    
    virtual_router_id 51    
    priority 100 #修改優先級    
    advert_int 1    
    authentication {    
        auth_type PASS    
        auth_pass 1111    
    }    
    virtual_ipaddress {    
        192.168.18.200    
    }    
}
virtual_server 192.168.18.200 80 {   
    delay_loop 6    
    lb_algo rr    
    lb_kind DR    
    nat_mask 255.255.255.0    
    #persistence_timeout 50    
    protocol TCP
    real_server 192.168.18.201 80 {   
        weight 1    
        HTTP_GET {    
            url {    
              path /    
          status_code 200    
            }    
            connect_timeout 2    
            nb_get_retry 3    
            delay_before_retry 1    
        }    
    }    
    real_server 192.168.18.202 80 {    
        weight 1    
        HTTP_GET {    
            url {    
              path /    
              status_code 200    
            }    
            connect_timeout 2    
            nb_get_retry 3    
            delay_before_retry 1    
        }    
    }    
}

5.啓動master與slave的keepalived服務

[root@master ~]# service keepalived start   
正在啓動 keepalived：                                      [肯定]
[root@slave ~]# service keepalived start   
正在啓動 keepalived：                                      [肯定]

6.查看一下LVS狀態

[root@master ~]# ipvsadm -L -n   
IP Virtual Server version 1.2.1 (size=4096)    
Prot LocalAddress:Port Scheduler Flags    
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn    
TCP  192.168.18.200:80 rr    
  -> 192.168.18.201:80            Route   1      0          0        
  -> 192.168.18.202:80            Route   1      0          0

7.測試

8.模擬故障

(1).中止一下node1

[root@node1 src]# service httpd stop   
中止 httpd：                                               [肯定]

(2).查看一下的lvs

[root@master ~]# ipvsadm -L -n   
IP Virtual Server version 1.2.1 (size=4096)    
Prot LocalAddress:Port Scheduler Flags    
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn    
TCP  192.168.18.200:80 rr    
  -> 192.168.18.202:80            Route   1      0          0

(3).測試一下

(4).查看一下郵件

(5).從新啓動一下node1

[root@node1 src]# service httpd start   
正在啓動 httpd：                                           [肯定]

(6).再查看一下lvs狀態

[root@master ~]# ipvsadm -L -n   
IP Virtual Server version 1.2.1 (size=4096)    
Prot LocalAddress:Port Scheduler Flags    
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn    
TCP  192.168.18.200:80 rr    
  -> 192.168.18.201:80            Route   1      0          0        
  -> 192.168.18.202:80            Route   1      0          0

(7).再查看一下郵件

(8).關閉master上keepalived

[root@master ~]# service keepalived stop   
中止 keepalived：                                          [肯定]    
[root@master ~]# ipvsadm -L -n    
IP Virtual Server version 1.2.1 (size=4096)    
Prot LocalAddress:Port Scheduler Flags    
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn

(9).查看一下slave狀態

[root@slave ~]# ip addr show   
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN    
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000    
    link/ether 00:0c:29:f9:e6:26 brd ff:ff:ff:ff:ff:ff    
    inet 192.168.18.207/24 brd 192.168.18.255 scope global eth0    
    inet 192.168.18.200/32 scope global eth0    
    inet6 fe80::20c:29ff:fef9:e626/64 scope link    
       valid_lft forever preferred_lft forever    
[root@slave ~]# ipvsadm -L -n    
IP Virtual Server version 1.2.1 (size=4096)    
Prot LocalAddress:Port Scheduler Flags    
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn    
TCP  192.168.18.200:80 rr    
  -> 192.168.18.201:80            Route   1      0          0        
  -> 192.168.18.202:80            Route   1      0          0

(10).再次測試一下

注，你們能夠看到，通過上面的演示咱們如今LVS的高可用即前端負載均衡的高可用，同時實現對後端realserver監控，也實現後端realserver宕機時會給管理員發送郵件。但還有幾個問題咱們尚未解決，問題以下:

全部realserver都down機，怎麼處理？是否是用戶就無法打開，仍是提供一下維護頁面。
怎麼完成維護模式keepalived切換？
如何在keepalived故障時，發送警告郵件給指定的管理員？

9.全部realserver都down機，怎麼處理？

問題：在集羣中若是全部real server所有宕機了，客戶端訪問時就會出現錯誤頁面，這樣是很不友好的，咱們得提供一個維護頁面來提醒用戶，服務器正在維護，什麼時間能夠訪問等，下面咱們就來解決一下這個問題。解決方案有兩種，一種是提供一臺備用的real server當全部的服務器宕機時，提供維護頁面，但這樣作有點浪費服務器。另外一種就是在負載均衡器上提供維護頁面，這樣是比較靠譜的，也比較經常使用。下面咱們就來具體操做一下。

(1).master與slave安裝上httpd

[root@master ~]# yum install -y httpd
[root@slave ~]# yum install -y httpd

(2).配置維護頁面

[root@master ~]# vim /var/www/html/index.html  
Website is currently under maintenance, please come back later!
 [root@slave ~]# vim /var/www/html/index.html 
Website is currently under maintenance, please come back later!

(3).啓動httpd服務並測試

[root@master ~]# service httpd start  
正在啓動 httpd：                                           [肯定]
[root@slave ~]# service httpd start  
正在啓動 httpd：                                           [肯定]

(4).修改配置文件

master:

[root@master ~]# cat /etc/keepalived/keepalived.conf   
! Configuration File for keepalived
global_defs {  
   notification_email {   
     15251076067@163.com   
   }   
   notification_email_from root   
   smtp_server 127.0.0.1   
   smtp_connect_timeout 30   
   router_id LVS_DEVEL   
}
vrrp_instance VI_1 {  
    state MASTER   
    interface eth0   
    virtual_router_id 51   
    priority 101   
    advert_int 1   
    authentication {   
        auth_type PASS   
        auth_pass 1111   
    }   
    virtual_ipaddress {   
        192.168.18.200   
    }   
}
virtual_server 192.168.18.200 80 {  
    delay_loop 6   
    lb_algo rr   
    lb_kind DR   
    nat_mask 255.255.255.0   
    protocol TCP
    real_server 192.168.18.201 80 {  
        weight 1   
        HTTP_GET {   
            url {   
              path /   
          status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    real_server 192.168.18.202 80 {   
        weight 1   
        HTTP_GET {   
            url {   
              path /   
              status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
   sorry_server 127.0.0.1 80   #增長一行sorry_server    
}

slave:

[root@slave ~]# cat /etc/keepalived/keepalived.conf   
! Configuration File for keepalived
global_defs {  
   notification_email {   
     15251076067@163.com   
   }   
   notification_email_from root   
   smtp_server 127.0.0.1   
   smtp_connect_timeout 30   
   router_id LVS_DEVEL   
}
vrrp_instance VI_1 {  
    state BACKUP   
    interface eth0   
    virtual_router_id 51   
    priority 100   
    advert_int 1   
    authentication {   
        auth_type PASS   
        auth_pass 1111   
    }   
    virtual_ipaddress {   
        192.168.18.200   
    }   
}
virtual_server 192.168.18.200 80 {  
    delay_loop 6   
    lb_algo rr   
    lb_kind DR   
    nat_mask 255.255.255.0   
    protocol TCP
    real_server 192.168.18.201 80 {  
        weight 1   
        HTTP_GET {   
            url {   
              path /   
          status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    real_server 192.168.18.202 80 {   
        weight 1   
        HTTP_GET {   
            url {   
              path /   
              status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    sorry_server 127.0.0.1 80 #增長一行sorry_server    
}

(5).關閉全部的real server並從新啓動一下master與slave的keepalived

[root@node1 ~]# service httpd stop  
中止 httpd：                                               [肯定]
[root@node2 ~]# service httpd stop  
中止 httpd：                                               [肯定]
[root@master ~]# service keepalived restart  
中止 keepalived：                                          [肯定]   
正在啓動 keepalived：                                      [肯定]
[root@slave ~]# service keepalived restart  
中止 keepalived：                                          [肯定]   
正在啓動 keepalived：                                      [肯定]

(6).查看一下lvs

[root@master ~]# ipvsadm -L -n  
IP Virtual Server version 1.2.1 (size=4096)   
Prot LocalAddress:Port Scheduler Flags   
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn   
TCP  192.168.18.200:80 rr   
  -> 127.0.0.1:80                 Local   1      0          0

(7).測試

注，sorry_server測試成功，下面咱們繼續。

10.怎麼完成維護模式keepalived切換？

問題：咱們通常進行主從切換測試時都是關閉keepalived或關閉網卡接口，有沒有一種方法能實如今不關閉keepalived下或網卡接口來實現維護呢？方法確定是有的，在keepalived新版本中，支持腳本vrrp_srcipt，具體如何使用你們能夠man keepalived.conf查看。下面咱們來演示一下具體怎麼實現。

(1).定義腳本

vrrp_srcipt chk_schedown {  
   script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"   
   interval 1 #監控間隔   
   weight -5 #減少優先級   
   fall 2 #監控失敗次數   
   rise 1 #監控成功次數   
}

(2).執行腳本

track_script {
   chk_schedown #執行chk_schedown腳本
}

(3).修改配置文件

master:

[root@master ~]# cat /etc/keepalived/keepalived.conf   
! Configuration File for keepalived
global_defs {  
   notification_email {   
     15251076067@163.com   
   }   
   notification_email_from root   
   smtp_server 127.0.0.1   
   smtp_connect_timeout 30   
   router_id LVS_DEVEL   
}
vrrp_script chk_schedown { #定義vrrp執行腳本   
   script "[ -e /etc/keepalived/down ] && exit 1 || exit 0" #查看是否有down文件，有就進入維護模式   
   interval 1 #監控間隔時間   
   weight -5 #下降優先級   
   fall 2 #失敗次數   
   rise 1 #成功數次   
}
vrrp_instance VI_1 {  
    state MASTER   
    interface eth0   
    virtual_router_id 51   
    priority 101   
    advert_int 1   
    authentication {   
        auth_type PASS   
        auth_pass 1111   
    }   
    virtual_ipaddress {   
        192.168.18.200   
    }   
    track_script { #執行腳本   
        chk_schedown   
    }   
}
virtual_server 192.168.18.200 80 {  
    delay_loop 6   
    lb_algo rr   
    lb_kind DR   
    nat_mask 255.255.255.0   
    protocol TCP
    real_server 192.168.18.201 80 {  
        weight 1   
        HTTP_GET {   
            url {   
              path /   
          status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    real_server 192.168.18.202 80 {   
        weight 1   
        HTTP_GET {   
            url {   
              path /   
              status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
   sorry_server 127.0.0.1 80   
}

slave:

[root@slave ~]# cat /etc/keepalived/keepalived.conf   
! Configuration File for keepalived
global_defs {  
   notification_email {   
     15251076067@163.com   
   }   
   notification_email_from root   
   smtp_server 127.0.0.1   
   smtp_connect_timeout 30   
   router_id LVS_DEVEL   
}
vrrp_script chk_schedown {  
   script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"   
   interval 1   
   weight -5   
   fall 2   
   rise 1   
}
vrrp_instance VI_1 {  
    state BACKUP   
    interface eth0   
    virtual_router_id 51   
    priority 100   
    advert_int 1   
    authentication {   
        auth_type PASS   
        auth_pass 1111   
    }   
    virtual_ipaddress {   
        192.168.18.200   
    }   
    track_script {   
    chk_schedown   
    }
}
virtual_server 192.168.18.200 80 {  
    delay_loop 6   
    lb_algo rr   
    lb_kind DR   
    nat_mask 255.255.255.0   
    protocol TCP
    real_server 192.168.18.201 80 {  
        weight 1   
        HTTP_GET {   
            url {   
              path /   
          status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    real_server 192.168.18.202 80 {   
        weight 1   
        HTTP_GET {   
            url {   
              path /   
              status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    sorry_server 127.0.0.1 80

(4).測試

master:

[root@master keepalived]# touch down #新建一下down文件
[root@master keepalived]# ll  
總用量 4   
-rw-r--r-- 1 root root    0 8月  22 13:39 down   
-rw-r--r-- 1 root root 1317 8月  22 13:35 keepalived.conf
[root@master keepalived]# tail -f /var/log/messages #查看一下日誌  
Aug 22 13:43:52 master Keepalived_vrrp[12003]: VRRP_Instance(VI_1) Entering MASTER STATE   
Aug 22 13:43:52 master Keepalived_vrrp[12003]: VRRP_Instance(VI_1) setting protocol VIPs.   
Aug 22 13:43:52 master Keepalived_vrrp[12003]: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth0 for 192.168.18.200   
Aug 22 13:43:52 master Keepalived_vrrp[12003]: VRRP_Instance(VI_1) Received higher prio advert   
Aug 22 13:43:52 master Keepalived_vrrp[12003]: VRRP_Instance(VI_1) Entering BACKUP STATE   
Aug 22 13:43:52 master Keepalived_vrrp[12003]: VRRP_Instance(VI_1) removing protocol VIPs.   
Aug 22 13:43:52 master Keepalived_healthcheckers[12002]: Netlink reflector reports IP 192.168.18.200 added   
Aug 22 13:43:52 master Keepalived_healthcheckers[12002]: Netlink reflector reports IP 192.168.18.200 removed   
Aug 22 13:43:52 master Keepalived_healthcheckers[12002]: SMTP alert successfully sent.   
Aug 22 13:43:52 master Keepalived_healthcheckers[12002]: SMTP alert successfully sent.   
^C   
[root@master keepalived]# ip add show #查看VIP   
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN    
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000   
    link/ether 00:0c:29:4b:a1:85 brd ff:ff:ff:ff:ff:ff   
    inet 192.168.18.208/24 brd 192.168.18.255 scope global eth0   
    inet6 fe80::20c:29ff:fe4b:a185/64 scope link    
       valid_lft forever preferred_lft forever

slave:

[root@slave ~]# ip addr show #查看一下VIP已轉移到slave上  
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN    
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000   
    link/ether 00:0c:29:f9:e6:26 brd ff:ff:ff:ff:ff:ff   
    inet 192.168.18.207/24 brd 192.168.18.255 scope global eth0   
    inet 192.168.18.200/32 scope global eth0   
    inet6 fe80::20c:29ff:fef9:e626/64 scope link    
       valid_lft forever preferred_lft forever

好了，自寫監測腳本，完成維護模式切換，到這裏就演示成功，下面咱們來解決最後一個問題，就是keepalived主從切換的郵件通告。

11.如何在keepalived故障時(或主備切換時)，發送警告郵件給指定的管理員？

(1).keepalived通知腳本進階示例

下面的腳本能夠接受選項，其中

-s, --service SERVICE,...：指定服務腳本名稱，當狀態切換時可自動啓動、重啓或關閉此服務；
-a, --address VIP: 指定相關虛擬路由器的VIP地址；
-m, --mode {mm|mb}：指定虛擬路由的模型，mm表示主主，mb表示主備；它們表示相對於同一種服務而方，其VIP的工做類型；
-n, --notify {master|backup|fault}：指定通知的類型，即vrrp角色切換的目標角色；
-h, --help：獲取腳本的使用幫助；

#!/bin/bash  
# Author: freeloda    
# description: An example of notify script   
# Usage: notify.sh -m|--mode {mm|mb} -s|--service SERVICE1,... -a|--address VIP  -n|--notify {master|backup|falut} -h|--help
contact='1521076067@163.com'
helpflag=0   
serviceflag=0   
modeflag=0   
addressflag=0   
notifyflag=0
Usage() {  
  echo "Usage: notify.sh [-m|--mode {mm|mb}] [-s|--service SERVICE1,...] <-a|--address VIP>  <-n|--notify {master|backup|falut}>"    
  echo "Usage: notify.sh -h|--help"   
}
ParseOptions() {  
  local I=1;   
  if [ $# -gt 0 ]; then   
    while [ $I -le $# ]; do   
      case $1 in   
      -s|--service)   
        [ $# -lt 2 ] && return 3   
         serviceflag=1   
         services=(`echo $2|awk -F"," '{for(i=1;i<=NF;i++) print $i}'`)   
        shift 2 ;;   
      -h|--help)   
         helpflag=1   
        return 0   
        shift   
        ;;   
      -a|--address)   
        [ $# -lt 2 ] && return 3   
        addressflag=1   
        vip=$2   
        shift 2   
        ;;   
      -m|--mode)   
        [ $# -lt 2 ] && return 3   
        mode=$2   
        shift 2   
        ;;   
      -n|--notify)   
        [ $# -lt 2 ] && return 3   
        notifyflag=1   
        notify=$2   
        shift 2   
        ;;   
      *)   
        echo "Wrong options..."   
        Usage   
        return 7   
        ;;   
       esac   
    done   
    return 0   
  fi   
}
#workspace=$(dirname $0)
RestartService() {  
  if [ ${#@} -gt 0 ]; then   
    for I in $@; do   
      if [ -x /etc/rc.d/init.d/$I ]; then   
        /etc/rc.d/init.d/$I restart   
      else   
        echo "$I is not a valid service..."   
      fi   
    done   
  fi   
}
StopService() {  
  if [ ${#@} -gt 0 ]; then   
    for I in $@; do   
      if [ -x /etc/rc.d/init.d/$I ]; then   
        /etc/rc.d/init.d/$I stop   
      else   
        echo "$I is not a valid service..."   
      fi   
    done   
  fi   
}
Notify() {   
    mailsubject="`hostname` to be $1: $vip floating"   
    mailbody="`date '+%F %H:%M:%S'`, vrrp transition, `hostname` changed to be $1."   
    echo $mailbody | mail -s "$mailsubject" $contact   
}
# Main Function   
ParseOptions $@   
[ $? -ne 0 ] && Usage && exit 5
[ $helpflag -eq 1 ] && Usage && exit 0
if [ $addressflag -ne 1 -o $notifyflag -ne 1 ]; then  
  Usage   
  exit 2   
fi
mode=${mode:-mb}
case $notify in  
'master')   
  if [ $serviceflag -eq 1 ]; then   
      RestartService ${services[*]}   
  fi   
  Notify master   
  ;;   
'backup')   
  if [ $serviceflag -eq 1 ]; then   
    if [ "$mode" == 'mb' ]; then   
      StopService ${services[*]}   
    else   
      RestartService ${services[*]}   
    fi   
  fi   
  Notify backup   
  ;;   
'fault')   
  Notify fault   
  ;;   
*)   
  Usage   
  exit 4   
  ;;   
esac

(2).在keepalived.conf配置文件中，其調用方法以下所示：

notify_master "/etc/keepalived/notify.sh -n master -a 192.168.18.200"
notify_backup "/etc/keepalived/notify.sh -n backup -a 192.168.18.200"
notify_fault "/etc/keepalived/notify.sh -n fault -a 192.168.18.200"

(3).修改配置文件

master:

[root@master keepalived]# cat keepalived.conf   
! Configuration File for keepalived
global_defs {  
   notification_email {   
     15251076067@163.com   
   }   
   notification_email_from root   
   smtp_server 127.0.0.1   
   smtp_connect_timeout 30   
   router_id LVS_DEVEL   
}
vrrp_script chk_schedown {  
   script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"   
   interval 1   
   weight -5   
   fall 2   
   rise 1   
}
vrrp_instance VI_1 {  
    state MASTER   
    interface eth0   
    virtual_router_id 51   
    priority 101   
    advert_int 1   
    authentication {   
        auth_type PASS   
        auth_pass 1111   
    }   
    virtual_ipaddress {   
        192.168.18.200   
    }   
    track_script {   
        chk_schedown   
    }
    #增長如下三行  
    notify_master "/etc/keepalived/notify.sh -n master -a 192.168.18.200"   
    notify_backup "/etc/keepalived/notify.sh -n backup -a 192.168.18.200" 
    notify_fault "/etc/keepalived/notify.sh -n fault -a 192.168.18.200" 
}
virtual_server 192.168.18.200 80 {  
    delay_loop 6   
    lb_algo rr   
    lb_kind DR   
    nat_mask 255.255.255.0   
    protocol TCP
    real_server 192.168.18.201 80 {  
        weight 1   
        HTTP_GET {   
            url {   
              path /   
          status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    real_server 192.168.18.202 80 {   
        weight 1   
        HTTP_GET {   
            url {   
              path /   
              status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
   sorry_server 127.0.0.1 80   
}

slave:

[root@slave keepalived]# cat keepalived.conf   
! Configuration File for keepalived
global_defs {  
   notification_email {   
     15251076067@163.com   
   }   
   notification_email_from root   
   smtp_server 127.0.0.1   
   smtp_connect_timeout 30   
   router_id LVS_DEVEL   
}
vrrp_script chk_schedown {  
   script "[ -e /etc/keepalived/down ] && exit 1 || exit 0"   
   interval 1   
   weight -5   
   fall 2   
   rise 1   
}
vrrp_instance VI_1 {  
    state BACKUP   
    interface eth0   
    virtual_router_id 51   
    priority 100   
    advert_int 1   
    authentication {   
        auth_type PASS   
        auth_pass 1111   
    }   
    virtual_ipaddress {   
        192.168.18.200   
    }   
    track_script {   
    chk_schedown   
    }
    #增長如下三行  
    notify_master "/etc/keepalived/notify.sh -n master -a 192.168.18.200" 
    notify_backup "/etc/keepalived/notify.sh -n backup -a 192.168.18.200"   
    notify_fault "/etc/keepalived/notify.sh -n fault -a 192.168.18.200"   
}
virtual_server 192.168.18.200 80 {  
    delay_loop 6   
    lb_algo rr   
    lb_kind DR   
    nat_mask 255.255.255.0   
    protocol TCP
    real_server 192.168.18.201 80 {  
        weight 1   
        HTTP_GET {   
            url {   
              path /   
          status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    real_server 192.168.18.202 80 {   
        weight 1   
        HTTP_GET {   
            url {   
              path /   
              status_code 200   
            }   
            connect_timeout 2   
            nb_get_retry 3   
            delay_before_retry 1   
        }   
    }   
    sorry_server 127.0.0.1 80   
}

(4).增長腳本

[root@slave keepalived]# pwd  
/etc/keepalived   
[root@slave keepalived]# vim notify.sh
[root@slave keepalived]# cat notify.sh   
#!/bin/bash   
# Author: freeloda    
# description: An example of notify script   
# Usage: notify.sh -m|--mode {mm|mb} -s|--service SERVICE1,... -a|--address VIP  -n|--notify {master|backup|falut} -h|--help
contact='15251076067@163.com'  
helpflag=0   
serviceflag=0   
modeflag=0   
addressflag=0   
notifyflag=0
Usage() {  
  echo "Usage: notify.sh [-m|--mode {mm|mb}] [-s|--service SERVICE1,...] <-a|--address VIP>  <-n|--notify {master|backup|falut}>"    
  echo "Usage: notify.sh -h|--help"   
}
ParseOptions() {  
  local I=1;   
  if [ $# -gt 0 ]; then   
    while [ $I -le $# ]; do   
      case $1 in   
      -s|--service)   
        [ $# -lt 2 ] && return 3   
         serviceflag=1   
         services=(`echo $2|awk -F"," '{for(i=1;i<=NF;i++) print $i}'`)   
        shift 2 ;;   
      -h|--help)   
         helpflag=1   
        return 0   
        shift   
        ;;   
      -a|--address)   
        [ $# -lt 2 ] && return 3   
        addressflag=1   
        vip=$2   
        shift 2   
        ;;   
      -m|--mode)   
        [ $# -lt 2 ] && return 3   
        mode=$2   
        shift 2   
        ;;   
      -n|--notify)   
        [ $# -lt 2 ] && return 3   
        notifyflag=1   
        notify=$2   
        shift 2   
        ;;   
      *)   
        echo "Wrong options..."   
        Usage   
        return 7   
        ;;   
       esac   
    done   
    return 0   
  fi   
}
#workspace=$(dirname $0)
RestartService() {  
  if [ ${#@} -gt 0 ]; then   
    for I in $@; do   
      if [ -x /etc/rc.d/init.d/$I ]; then   
        /etc/rc.d/init.d/$I restart   
      else   
        echo "$I is not a valid service..."   
      fi   
    done   
  fi   
}
StopService() {  
  if [ ${#@} -gt 0 ]; then   
    for I in $@; do   
      if [ -x /etc/rc.d/init.d/$I ]; then   
        /etc/rc.d/init.d/$I stop   
      else   
        echo "$I is not a valid service..."   
      fi   
    done   
  fi   
}
Notify() {   
    mailsubject="`hostname` to be $1: $vip floating"   
    mailbody="`date '+%F %H:%M:%S'`, vrrp transition, `hostname` changed to be $1."   
    echo $mailbody | mail -s "$mailsubject" $contact   
}
# Main Function   
ParseOptions $@   
[ $? -ne 0 ] && Usage && exit 5
[ $helpflag -eq 1 ] && Usage && exit 0
if [ $addressflag -ne 1 -o $notifyflag -ne 1 ]; then  
  Usage   
  exit 2   
fi
mode=${mode:-mb}
case $notify in  
'master')   
  if [ $serviceflag -eq 1 ]; then   
      RestartService ${services[*]}   
  fi   
  Notify master   
  ;;   
'backup')   
  if [ $serviceflag -eq 1 ]; then   
    if [ "$mode" == 'mb' ]; then   
      StopService ${services[*]}   
    else   
      RestartService ${services[*]}   
    fi   
  fi   
  Notify backup   
  ;;   
'fault')   
  Notify fault   
  ;;   
*)   
  Usage   
  exit 4   
  ;;   
esac

(5).給腳本增長執行權限

[root@slave keepalived]# chmod +x notify.sh

(6).將master上腳本複製到slave上

[root@slave keepalived]# scp -p notify.sh root@192.168.18.207:/etc/keepalived/

(7).測試一下腳本

[root@slave keepalived]# ./notify.sh -h  
Usage: notify.sh [-m|--mode {mm|mb}] [-s|--service SERVICE1,...] <-a|--address VIP>  <-n|--notify {master|backup|falut}>   
Usage: notify.sh -h|--help   
[root@slave keepalived]# ./notify.sh --help   
Usage: notify.sh [-m|--mode {mm|mb}] [-s|--service SERVICE1,...] <-a|--address VIP>  <-n|--notify {master|backup|falut}>   
Usage: notify.sh -h|--help   
[root@slave keepalived]# ./notify.sh -m mb -a 1.1.1.1 -n master

(8).查看一下郵件

注，你們能夠看到成功收到郵件，測試成功。在模擬故障時先重啓一下keepalived服務。

(9).模擬故障

[root@master keepalived]# ip addr show #查看一下VIP  
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN    
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000   
    link/ether 00:0c:29:4b:a1:85 brd ff:ff:ff:ff:ff:ff   
    inet 192.168.18.208/24 brd 192.168.18.255 scope global eth0   
    inet 192.168.18.200/32 scope global eth0   
    inet6 fe80::20c:29ff:fe4b:a185/64 scope link    
       valid_lft forever preferred_lft forever   
[root@master keepalived]# touch down #進入維護模式   
[root@master keepalived]# ll   
總用量 8   
-rw-r--r-- 1 root root    0 8月  22 14:39 down   
-rw-r--r-- 1 root root 1543 8月  22 14:04 keepalived.conf   
-rwxr-xr-x 1 root root 2516 8月  22 14:15 notify.sh   
[root@master keepalived]# ip addr show #再次查看VIP   
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN    
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000   
    link/ether 00:0c:29:4b:a1:85 brd ff:ff:ff:ff:ff:ff   
    inet 192.168.18.208/24 brd 192.168.18.255 scope global eth0   
    inet6 fe80::20c:29ff:fe4b:a185/64 scope link    
       valid_lft forever preferred_lft forever
[root@slave keepalived]# ip addr show #你們能夠看到VIP成功移動到slave上  
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN    
    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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000   
    link/ether 00:0c:29:f9:e6:26 brd ff:ff:ff:ff:ff:ff   
    inet 192.168.18.207/24 brd 192.168.18.255 scope global eth0   
    inet 192.168.18.200/32 scope global eth0   
    inet6 fe80::20c:29ff:fef9:e626/64 scope link    
       valid_lft forever preferred_lft forever

(10).查看一下郵件

注，你們能夠看到，主備切換時，會發送郵件報警，好了到這裏全部演示所有完成。但願你們有所收穫^_^……