【 Keepalived 】Nginx or Http 主-备模式

一、主-备模式：

　　操作系统：centos 6.4 x64

　　ka1: 192.168.2.10

　　ka2: 192.168.2.11

　　vip: 192.168.2.200

ka1-master服务器配置

[ka1 root@192.168.2.10 ~]#yum install  httpd keepalived -y　　　　# 这里使用apache代替nginx，效果是一样的，然后直接yum安装keepalived
[ka1 root@192.168.2.10 ~]#sed -i 's@#ServerName www.example.com:80@ServerName localhost:80@g' /etc/httpd/conf/httpd.conf
[ka1 root@192.168.2.10 ~]#service httpd start　　# 启动httpd
正在启动 httpd：                                           [确定]
[ka1 root@192.168.2.10 ~]#echo "192.168.2.10" >> /var/www/html/index.html　　# 添加测试页面
[ka1 root@192.168.2.10 ~]#curl -I 192.168.2.10　　# 测试访问http header 返回是否正常。这里为200 正常。
HTTP/1.1  OK
Date: Sun,  Dec  :: GMT
Server: Apache/2.2. (CentOS)
Last-Modified: Sun,  Dec  :: GMT
ETag: "5ff81-d-52638dd3bc5ea"
Accept-Ranges: bytes
Content-Length:
Connection: close
Content-Type: text/html; charset=UTF-
[ka1 root@192.168.2.10 ~]#cd /etc/keepalived/
[ka1 root@192.168.2.10 /etc/keepalived]#ls
keepalived.conf
[ka1 root@192.168.2.10 /etc/keepalived]#cp -a keepalived.conf keepalived.conf_bak　　# 编写配置前一定要备份。
[ka1 root@192.168.2.10 /etc/keepalived]#vim keepalived.conf　　# keepalived配置如下：
! Configuration File for keepalived

global_defs {
   notification_email {
     root@localhost　　　　# 故障发生时给谁发邮件通知。这里使用root用户发送给本机
   }
   notification_email_from root@localhost　　# 通知邮件从哪个地址发出
   smtp_server localhost　　# 通知邮件的smtp地址。
   smtp_connect_timeout 30　　# 连接smtp服务器的超时时间。
   router_id NodeA　　# 标识本节点的字条串，通常为hostname，但不一定非得是hostname。故障发生时，邮件通知会用到。
}

vrrp_script check_nginx {　　　　# 创建健康检测脚本
   script "/etc/keepalived/bash/check_nginx.sh"　　# 脚本具体位置，这里注意：脚本是一定要有执行权限的。
   interval 5　　# 脚本运行间隔
   weight -10　　# 如果脚本执行失败，vrrp_instance的优先级会减少10个点。
}

vrrp_instance VI_1 {　　# 用来定义对外提供服务的VIP区域及其相关属性。
    state MASTER　　# 可以是MASTER或BACKUP，不过当其他节点keepalived启动时会将priority比较大的节点选举为MASTER，因此该项其实没有实质用途。
    interface eth0　　# 节点固有IP（非VIP）的网卡，用来发VRRP包。该网卡应该为vip绑定的网卡
    virtual_router_id 51　　# 取值在0-255之间，用来区分多个instance的VRRP组播。注意： 同一网段中virtual_router_id的值不能重复，否则会出错，相关错误信息如下。
    priority 100　　# 用来选举master的，要成为master，那么这个选项的值最好高于其他机器50个点，该项取值范围是1-255（在此范围之外会被识别成默认值100）。
    advert_int 1　　# 发VRRP包的时间间隔，即多久进行一次master选举（可以认为是健康查检时间间隔）。
    authentication {　　# 认证区域，认证类型有PASS和HA（IPSEC），推荐使用PASS（密码只识别前8位）。
        auth_type PASS
        auth_pass
    }
    track_script {　　# 在VI_1区域使用上面定义的check_nginx进行健康检测
        check_nginx
    }
    virtual_ipaddress {　　# vip，不解释了。注意：这里设置VIP的时候一定要把掩码带上。
        192.168.2.200/24
    }
}

以上红色部分为修改内容部分。

[ka1 root@192.168.2.10 /etc/keepalived]#mkdir bash　　
[ka1 root@192.168.2.10 /etc/keepalived/bash]#vim check_nginx.sh　　# 编写脚本，内容如下，很简单，这里不多做解释。
#!/bin/bash

pidfile=/var/lock/subsys/`basename $`.pid
if [ -f $pidfile ] && [ -e /proc/`cat $pidfile` ] ; then
    exit
fi
trap "rm -rf $pidfile ; exit 0"
echo $$ > $pidfile
maxfails=
fails=
success=

while [  ]
do

    /usr/bin/wget --timeout= --tries= http://192.168.2.10/ -q -O /dev/null && ping -c1 192.168.2.1 &> /dev/null
    if [ $? -ne  ] ; then
        let fails=$[$fails+]
        success=
    else
        fails=
        let success=$[$success+]
    fi

    if [ $fails -ge $maxfails ] ; then
        fails=
        success=
        #check keepalived is running ? try to stop it
        /etc/init.d/keepalived status | grep running
        if [ $? -eq  ] ; then
            /bin/logger -is "local service fails $maxfails times ... try to stop keepalived."
            /etc/init.d/keepalived stop >& | /bin/logger
        fi

    fi

    if [ $success -gt $maxfails ] ; then
        #check keepalived is stopped ? try to start it
        /etc/init.d/keepalived status | grep 已停　　　　# 脚本中这里要注意，如果系统是英文安装的为 grep stopped 如果是中文为 grep 已停
        if [ $? -eq  ] ; then
            logger -is "service changes normal, try to start keepalived ."
            /etc/init.d/keepalived start
        fi
        success=
    fi
    sleep 

done

[ka1 root@192.168.2.10 /etc/keepalived/bash]#chmod +x check_nginx.sh
[ka1 root@192.168.2.10 /etc/keepalived]#service keepalived start
正在启动 keepalived：                                      [确定]
[ka1 root@192.168.2.10 /etc/keepalived/bash]#ip a
: lo: <LOOPBACK,UP,LOWER_UP> mtu  qdisc noqueue state UNKNOWN
    link/loopback ::::: brd :::::
    inet 127.0.0.1/ scope host lo
    inet6 ::/ scope host
       valid_lft forever preferred_lft forever
: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu  qdisc pfifo_fast state UP qlen
    link/ether :0c::::4f brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.10/ brd 192.168.2.255 scope global eth0
    inet 192.168.2.200/ scope global secondary eth0　　　　# 这里就已经绑定上了VIP
    inet6 fe80::20c:29ff:fe39:924f/ scope link
       valid_lft forever preferred_lft forever

[ka1 root@192.168.2.10 /etc/keepalived/bash]#ps auxfww | grep check_nginx.sh　　# 查看配置文件中的脚本是否正常运行。
root         0.0  0.0     pts/    S+   :   :          \_ grep check_nginx.sh
root         0.0  0.1    ?        S    :   : /bin/bash /etc/keepalived/bash/check_nginx.sh
[ka1 root@192.168.2.10 /etc/keepalived/bash]#service keepalived stop　　　　# 关闭keepalived进行测试。
停止 keepalived：                                          [确定]
[ka1 root@192.168.2.10 /etc/keepalived/bash]#service keepalived status　　　# 等一会就可以看到keepalived
keepalived (pid  ) 正在运行...

ka1 master主机配置完毕，ka2配置如下：

[ka2 root@192.168.2.11 ~]#yum install httpd keepalived -y
[ka2 root@192.168.2.11 ~]#sed -i 's@#ServerName www.example.com:80@ServerName localhost:80@g' /etc/httpd/conf/httpd.conf
[ka2 root@192.168.2.11 ~]#service httpd start
正在启动 httpd：                                           [确定]
[ka2 root@192.168.2.11 ~]#curl -I 192.168.2.11
HTTP/1.1  OK
Date: Sun,  Dec  :: GMT
Server: Apache/2.2. (CentOS)
Last-Modified: Sun,  Dec  :: GMT
ETag: "5fe4e-d-526396f6ac030"
Accept-Ranges: bytes
Content-Length:
Connection: close
Content-Type: text/html; charset=UTF-

[ka2 root@192.168.2.11 ~]#cd /etc/keepalived/
[ka2 root@192.168.2.11 /etc/keepalived]#ls
keepalived.conf
[ka2 root@192.168.2.11 /etc/keepalived]#cp -a keepalived.conf keepalived.conf_bak
[ka2 root@192.168.2.11 /etc/keepalived]#scp 192.168.2.10:/etc/keepalived/keepalived.conf .
The authenticity of host '192.168.2.10 (192.168.2.10)' can't be established.
RSA key fingerprint is be:e8::ba:fd:::ed:::f5:::::.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.2.10' (RSA) to the list of known hosts.
root@192.168.2.10's password:
keepalived.conf                                                                                                                                            %       .6KB/s   : 

[ka2 root@192.168.2.11 /etc/keepalived]#vim keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from root@localhost
   smtp_server localhost
   smtp_connect_timeout
   router_id NodeB
}

vrrp_script check_nginx {
   script "/etc/keepalived/bash/check_nginx.sh"
   interval
   weight -
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id
    priority
    advert_int
    authentication {
        auth_type PASS
        auth_pass
    }
    track_script {
        check_nginx
    }
    virtual_ipaddress {
        192.168.2.200/
    }
}
红色部分为修改内容
[ka2 root@192.168.2.11 /etc/keepalived]#mkdir bash
[ka2 root@192.168.2.11 /etc/keepalived]#cd bash
[ka2 root@192.168.2.11 /etc/keepalived/bash]#scp 192.168.2.10:/etc/keepalived/bash/check_nginx.sh .　　# 这里脚本拷贝过来以后，需要修改下IP地址。
root@192.168.2.10's password:
check_nginx.sh                                                                                                                                             %      .2KB/s   :
[ka2 root@192.168.2.11 /etc/keepalived]#service keepalived restart
停止 keepalived：                                          [确定]
正在启动 keepalived：                                      [确定]

[ka2 root@192.168.2.11 /etc/keepalived]#ps auxfww  | grep check_nginx.sh
root         0.0  0.0     pts/    S+   :   :  |       \_ grep check_nginx.sh
root         0.0  0.1    ?        S    :   : /bin/bash /etc/keepalived/bash/check_nginx.sh
[ka2 root@192.168.2.11 /var]#service keepalived stop
停止 keepalived：                                          [确定]
[ka2 root@192.168.2.11 /etc/keepalived]#service keepalived status
keepalived (pid  ) 正在运行...

两台keepalived主机配置完毕，测试如下：

aaarticlea/png;base64,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" alt="" />

keepalived设置ka1为Master   IP: 192.168.2.10

接下来down掉 ka1的httpd服务，再次访问：

aaarticlea/png;base64,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" alt="" />

当ka1 master 主机故障解除，启动httpd进程后，再次访问：

aaarticlea/png;base64,iVBORw0KGgoAAAANSUhEUgAAAQ8AAAB8CAIAAAD4jKKyAAAIuklEQVR4nO2dP3KjMBSHOQJXYDjBnoHCxfY5AQ11uEDo3DndVnQ7NL4AtcfV7ngm9J5xnZILeIu3efMsgfzAyNjk91VZLUiy8z70j0hBC4AH/i6RYO5vFSyTuQPbC7AFeGHuwPYCbAFemDuwvQBbgBfmDmwvwBbghbkD2wuwBXhh7sD2AmwBXpg7sL0AW4AX5g5sL7hsqdXc7XcAnoW5A9sLLluCIEgUBAEaKGAyNBDf3t7e3t58hPiEXLFF873AloXx+vp6OBzs9MPh8Pr6qsxkaCAuwZZCAWxZGIfD4efPn4YwnYkOhgYibLnIh36u6zoIgiAIoijiC6g7Rx0/+/Y0TeXFTdMEX8giiKZp7NvtEu0buYayPmVZcmIURZT4HcZphhtDVWm/py2a78VxGblUliXFYtM0HLJFUaRp2n7NJXCijFoSoyxLvotSjFKSJKGwruvaUKJpGo74siypRFk9mQlVgytGH430S9OUP8I3aUvZkBGqtLBl9GVsS1EU8mlttyR1XcsIZtiBNE3tR7s0pLMBIZqmMWyRFEVBOcscuOYy0fgUC4Y8GaFKq7Dl7ZKXl5eXlxcj8Q4CDGJOW+zI5pA14CuTJKH2Svad0jTltqWzL8fVcEQ53yhzqOs6TVNDM/44iwe2GNzVFtlTKsvSuJF7OzZ8l5SE+07t16DC0bDI/lVn/pwVbCHQE7O5qy3tlyRBEKRpKuPSGFIbsAbSB+62RVFEo4u+QUUURX3xTbMOcm4AtrQY5fdwb1uYpmkoLjXjZoctFNCcaPflOifKuGJ2z61ziCITO8dOSwIzyH3cYy2/0xbu/PSNVYyL6Qc5aUY5GLIZbijHKhJZBOfMQyM5rbdUsDrZxz3eE5MzyLy+wXfxeohccjH6aZ2LM6wBr+FwIveveEpALrkURUE/8BKKMW3ARciPxhf3tVRAMjQQn94WAEYzd2B7AbYAL8wd2F6ALcALcwe2F2AL8MLcge0F2AK8MHdgewG2AC/MHdhegC3AC3MHthdgC/DC3IHtBdgCvDB3YHsBtgAvzB3YXoAtAGiBLQBogS0AaIEtAGiBLQBogS0AaIEtAGiBLQBogS0AaIEti+X9/X3uKiwN2LJYYMvkwJbFAlsmZxpbTqfTJPlMyOfn59xVmBnYMjkT2FKW5Y8fPx5KmM/Pz9+/f398fMxSOm9HFlgn0mw2m7vtcwlbJudWW2hf4wc8oeHj4+P9/X0WYfb7/WazCcPQtqUoijAMkyTZ7/e+qwFbJucmWx5WFWIuYfb7fRiGeZ7neW5vHns6nfI8D8PQtzAjbDHOSJObgHIit5x9O9waZ7kZ+cj93e0NQTVF8I1y/2veSVRGo6OIcYy35cFVIe4vDKlCX0tRFH3nyZRl6VuYQbZQgMpDQSigKbj5g8h9pZMkMQ75oJAwbCFVjOKiKJJ78BqZOIqgIw/oZw4/OtWnvTwxgYuwzz4ZzchcnkIV4s7CJEmS5zn9XNe14yvqbHkmZETbIm0xTryxN4DuPKGgtc4zlMfsdObm2Fq6rwhZW2PbeDLHqAObcyNjbHkiVYi7CVPXdRiGygmP0+kUhqG/Qf+0tsgDofjizgOk7Ejlvdv5ei7IPgxUUwTnXJalURxV29DMcZDWIAbb8nSqEPcRJk1Tblg05HnuiIYbudEW2auhX7q0xXGWtQxfevDLEz5k78g42sDAfVw2nYbSWnI+kC1PqgpxB2HsB7Ab+xDmCbnRlvbyIDc+gK1t2yiKHB0k2xb+Lwpl4zy2zlG4owjDwAe1hb47mgAdyu0VtdkO59evX16FGTr90jkCnorbbWHkGU9XH5dG+Nq2XA1lRxH2yYf2uMXung19ivUx4Fe12WyWYcufP3981Kddri0Ugm3PYbfGzJU9ypc9MToey25beObKXQTXxPhfOSdGiXJObKoGHD2xKVlYT8weWhgHuVFoum1puxZD5LjFmOd1F2Ec58YPYk5hCeWSztDvoQ+M8qfk2Uf5wA1mkKdku90OnUHebreeKgNbJgerkxMjVyfdPODqJHCDN18mRr754uDR3nwBGvBW5fTwW5WdXbJHfqsSuMEb+17Y7/dJkpAztYA8SfDG/nOCvwbzyHa7pVVwmseMoihNU3/DegPYMjn4S+PFAlsmB7tYLBbYMjmwZbHAlsmBLYsFtkwObAFAC2wBQAtsAUALbAFAC2wBQAtsAUALbAFAC2wBQAtsAUBL8BcAoCM4AwB0wBYAtMAWALTAFgC0wBYAtMAWALTAFgC0wBYAtMAWALTAFgC0wBYAtMAWALRct2W1WsVxbCfSbqXr9foiuy+qqhqaJ7FerymH4/FolLVarXo/xg3lVlWluRcAly3H45HCyIiw1WqVZdn/+4UwfBlFfGfw9eXJuQXBRZWyLOMrsyzjciW3lFtVFafEcQxhgIPrbYuM1/NX2PE/6cF8Pp93ux23BufzOY7jzsjuzPN/VbpajziO2caqquwLbixXGiLNAcBmsC2sB0Hy7HY74y7Z/lzNszOF82FDqqpy5DmiXKo8y2b8EwCDkbawHg5bHL0a2w3q0fHwg0N2t9sFQZBl2fF4dIxbxpWrNB8AYrAt58suE0WzEWFXI9vIkzLhW+I4tmNa00caWi5sAYMYYwuPmBnjltVq5e7PuKPWMJBy6yxo2nJhC3AzxhaJHIUT6/X6asDpozbLMs7fMe88rlxjoEKWYtwC+rjJlvV6bU/IGvJo8jQe6jKI5YywYxQ+rtyzNSemGRqBb8t4W+I4NrpGxpyV42Fv5ynFk+sqsj3pm+G9pVyZJ7phwM0VW+TghCKJhxB2B8wYzPSN2u08iSzLKNGYAiYtjYE+53l7uZwDliaBG7wnBoAW2AKAFtgCgBbYAoAW2AKAFtgCgBbYAoAW2AKAFtgCgBbYAoAW2AKAFtgCgBbYAoAW2AKAFtgCgBbYAoAW2AKAFtgCgBbYAoAW2AKAFtgCgBbYAoAW2AKAFtgCgJZ/Ge0c1QBxOokAAAAASUVORK5CYII=" alt="" />

这种主备模式的使用，BACKUP主机只是作为备用主机，一旦MASTER主机故障解除，就要拿回主权。在配置过程中，如果出现问题，多查看/var/log/messages 日志文件，我在配置过程中曾出现过问题。

如果在测试环节出现问题，请使用 sh -x 脚本名来排查脚本问题。