keepalived+nginx双机热备+负载均衡

keepalived+nginx双机热备+负载均衡
最近因业务扩展，需要将当前的apache 转为nginx(web), 再在web前端放置nginx(负载均衡)。同时结合keepalived 对前端nginx实现HA。 nginx进程基于于Master+Slave(worker)多进程模型，自身具有非常稳定的子进程管理功能。在Master进程分配模式下，Master进程永远不进行业务处理，只是进行任务分发，从而达到Master进程的存活高可靠性，Slave(worker)进程所有的业务信号都 由主进程发出，Slave(worker)进程所有的超时任务都会被Master中止，属于非阻塞式任务模型。 Keepalived是Linux下面实现VRRP 备份路由的高可靠性运行件。基于Keepalived设计的服务模式能够真正做到主服务器和备份服务器故障时IP瞬间无缝交接。二者结合，可以构架出比较稳定的软件lb方案。

准备4台电脑来做这个实验:
192.168.232.132        web服务器 192.168.232.133        web服务器 192.168.232.134        keepalived nginx 192.168.232.135        keepalived nginx
虚拟IP (VIP)：192.168.232.16

134135两个主机配置虚拟IP

下面以135为例：
vi /etc/sysconfig/network-scripts/ifcfg-eth2:0

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. DEVICE=eth2:0  
  2. TYPE=Ethernet  
  3. ONBOOT=yes  
  4. BOOTPROTO=static  
  5. DNS1=192.168.232.2  
  6. IPADDR=192.168.232.16  
  7. NETMASK=255.255.255.0  
  8. GETWAY=192.168.232.2  
 
DEVICE=eth2:0
TYPE=Ethernet
ONBOOT=yes
BOOTPROTO=static
DNS1=192.168.232.2
IPADDR=192.168.232.16
NETMASK=255.255.255.0
GETWAY=192.168.232.2

service network restart
使用ifconfig查看效果：

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. eth2      Link encap:Ethernet  HWaddr 00:0C:29:49:90:5B    
  2.           inet addr:192.168.232.135  Bcast:192.168.232.255  Mask:255.255.255.0  
  3.           inet6 addr: fe80::20c:29ff:fe49:905b/64 Scope:Link  
  4.           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1  
  5.           RX packets:66322 errors:0 dropped:0 overruns:0 frame:0  
  6.           TX packets:31860 errors:0 dropped:0 overruns:0 carrier:0  
  7.           collisions:0 txqueuelen:1000  
  8.           RX bytes:67624991 (64.4 MiB)  TX bytes:2723877 (2.5 MiB)  
  9.           Interrupt:19 Base address:0x2000  
  10.   
  11. eth2:0    Link encap:Ethernet  HWaddr 00:0C:29:49:90:5B    
  12.           inet addr:192.168.232.16  Bcast:192.168.232.255  Mask:255.255.255.0  
  13.           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1  
  14.           Interrupt:19 Base address:0x2000  
  15.   
  16. lo        Link encap:Local Loopback    
  17.           inet addr:127.0.0.1  Mask:255.0.0.0  
  18.           inet6 addr: ::1/128 Scope:Host  
  19.           UP LOOPBACK RUNNING  MTU:16436  Metric:1  
  20.           RX packets:22622 errors:0 dropped:0 overruns:0 frame:0  
  21.           TX packets:22622 errors:0 dropped:0 overruns:0 carrier:0  
  22.           collisions:0 txqueuelen:0  
  23.           RX bytes:1236328 (1.1 MiB)  TX bytes:1236328 (1.1 MiB)  
eth2      Link encap:Ethernet  HWaddr 00:0C:29:49:90:5B  
          inet addr:192.168.232.135  Bcast:192.168.232.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe49:905b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:66322 errors:0 dropped:0 overruns:0 frame:0
          TX packets:31860 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:67624991 (64.4 MiB)  TX bytes:2723877 (2.5 MiB)
          Interrupt:19 Base address:0x2000

eth2:0    Link encap:Ethernet  HWaddr 00:0C:29:49:90:5B  
          inet addr:192.168.232.16  Bcast:192.168.232.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          Interrupt:19 Base address:0x2000

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:22622 errors:0 dropped:0 overruns:0 frame:0
          TX packets:22622 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1236328 (1.1 MiB)  TX bytes:1236328 (1.1 MiB)

           说明生效了。

134135两个主机安装keepalived和nginx

nginx安装：
1、导入外部软件库 rpm -Uvh http://dl.iuscommunity.org/pub/ius/stable/Redhat/6/i386/epel-release-6-5.noarch.rpm rpm -Uvh http://dl.iuscommunity.org/pub/ius/stable/Redhat/6/i386/ius-release-1.0-10.ius.el6.noarch.rpm rpm -Uvh http://nginx.org/packages/centos/6/noarch/RPMS/nginx-release-centos-6-0.el6.ngx.noarch.rpm 以下添加注释 mirrorlist=http://dmirr.iuscommunity.org/mirrorlist?repo=ius-el6&arch=$basearch 以下删除注释 #baseurl=http://dl.iuscommunity.org/pub/ius/stable/Redhat/5/$basearch 2、yum安装nginx yum install nginx
keepalived安装：
安装依赖 yum -y install gcc gcc+ gcc-c++ yum install popt-devel openssl openssl-devel libssl-dev libnl-devel popt-devel
安装内核 yum -y install kernel kernel-devel 当前kernel代码建立连接 ln -s /usr/src/kerners/2.6....../ /usr/src/linux
安装keepalived wget http://www.keepalived.org/software/keepalived-1.2.2.tar.gz tar -zxvf keepalived-1.2.2.tar.gz   cd keepalived-1.2.2   ./configure   make   make install   
拷贝相应的文件
cp /usr/local/sbin/keepalived /usr/sbin/ cp /usr/local/etc/rc.d/init.d/keepalived /etc/init.d/   cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/   cp -r /usr/local/etc/keepalived/ /etc/  

配置keeplived和nginx主机

134/135执行都执行以下操作： vi /etc/nginx/conf.d/default.conf

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. server {  
  2.     listen       8088;  
  3.     server_name  localhost;  
  4.   
  5.     location / {  
  6.         root   /var/www/html;  
  7.         index  index.html index.htm;  
  8.     }  
  9.   
  10.     error_page   500 502 503 504  /50x.html;  
  11.     location = /50x.html {  
  12.         root   /usr/share/nginx/html;  
  13.     }  
  14. }  
 
server {
    listen       8088;
    server_name  localhost;

    location / {
        root   /var/www/html;
        index  index.html index.htm;
    }

    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }
}

135执行以下操作： vi /var/www/html/index.html

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. <html>    
  2. <head>    
  3. <title>Welcome to nginx!</title>    
  4. </head>    
  5. <body bgcolor="white" text="black">    
  6. <center><h1>Welcome to nginx! 192.168.232.135</h1></center>    
  7. </body>    
  8. </html>  
 
<html>  
<head>  
<title>Welcome to nginx!</title>  
</head>  
<body bgcolor="white" text="black">  
<center><h1>Welcome to nginx! 192.168.232.135</h1></center>  
</body>  
</html>

134执行以下操作： vi /var/www/html/index.html

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. <html>    
  2. <head>    
  3. <title>Welcome to nginx!</title>    
  4. </head>    
  5. <body bgcolor="white" text="black">    
  6. <center><h1>Welcome to nginx! 192.168.232.134</h1></center>    
  7. </body>    
  8. </html>  
 
<html>  
<head>  
<title>Welcome to nginx!</title>  
</head>  
<body bgcolor="white" text="black">  
<center><h1>Welcome to nginx! 192.168.232.134</h1></center>  
</body>  
</html>

134执行以下操作： vi /etc/keepalived/keepalived.conf

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. ! Configuration File for keepalived  
  2.   
  3. global_defs {  
  4.    notification_email {  
  5.      #acassen@firewall.loc  
  6.      #failover@firewall.loc  
  7.      #sysadmin@firewall.loc  
  8.    }  
  9.    #notification_email_from Alexandre.Cassen@firewall.loc  
  10.    #smtp_server 192.168.200.1  
  11.    #smtp_connect_timeout 30  
  12.    router_id LVS_DEVEL  
  13. }  
  14.   
  15. vrrp_script chk_http_port {  
  16.     script "</dev/tcp/127.0.0.1/8088"  
  17.     interval 1  
  18.     weight -2  
  19. }  
  20.   
  21. vrrp_instance VI_1 {  
  22.     state MASTER  
  23.     interface eth2  
  24.     virtual_router_id 51  
  25.     priority 100  
  26.     advert_int 1  
  27.     authentication {  
  28.         auth_type PASS  
  29.         auth_pass 1111  
  30.     }  
  31.     virtual_ipaddress {  
  32.         192.168.232.16  
  33.     }  
  34.     track_script {  
  35.         chk_http_port  
  36.     }  
  37. }     
! Configuration File for keepalived

global_defs {
   notification_email {
     #acassen@firewall.loc
     #failover@firewall.loc
     #sysadmin@firewall.loc
   }
   #notification_email_from Alexandre.Cassen@firewall.loc
   #smtp_server 192.168.200.1
   #smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_http_port {
    script "</dev/tcp/127.0.0.1/8088"
    interval 1
    weight -2
}

vrrp_instance VI_1 {
    state MASTER
    interface eth2
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.232.16
    }
    track_script {
        chk_http_port
    }
}

135执行以下操作： vi /etc/keepalived/keepalived.conf

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. ! Configuration File for keepalived  
  2.   
  3. global_defs {  
  4.    notification_email {  
  5.      #acassen@firewall.loc  
  6.      #failover@firewall.loc  
  7.      #sysadmin@firewall.loc  
  8.    }  
  9.    #notification_email_from Alexandre.Cassen@firewall.loc  
  10.    #smtp_server 192.168.200.1  
  11.    #smtp_connect_timeout 30  
  12.    router_id LVS_DEVEL  
  13. }  
  14.   
  15. vrrp_script chk_http_port {  
  16.     script "</dev/tcp/127.0.0.1/8088"  
  17.     interval 1  
  18.     weight -2  
  19. }  
  20.   
  21. vrrp_instance VI_1 {  
  22.     state BACKUP  
  23.     interface eth2  
  24.     virtual_router_id 51  
  25.     priority 99  
  26.     advert_int 1  
  27.     authentication {  
  28.         auth_type PASS  
  29.         auth_pass 1111  
  30.     }  
  31.     virtual_ipaddress {  
  32.         192.168.232.16  
  33.     }  
  34.     track_script {  
  35.         chk_http_port  
  36.     }  
  37. }  
! Configuration File for keepalived

global_defs {
   notification_email {
     #acassen@firewall.loc
     #failover@firewall.loc
     #sysadmin@firewall.loc
   }
   #notification_email_from Alexandre.Cassen@firewall.loc
   #smtp_server 192.168.200.1
   #smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_script chk_http_port {
    script "</dev/tcp/127.0.0.1/8088"
    interval 1
    weight -2
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth2
    virtual_router_id 51
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.232.16
    }
    track_script {
        chk_http_port
    }
}

Tips：
state   参数值：主的是MASTER、备用的是BACKUP priority 参数值： MASTER > BACKUP virtual_router_id： 参数值要一样

测试测试：

两台测试机134135均启动keepalived和nginx service keepalived restart service keepalived nginx
验证nginx启动正常： 访问 master：http://192.168.232.134:8088/ 访问 backup: http://192.168.232.135:8088/
查看keepalived的日志信息：
134135均打开日志信息方便查看keepalived动态： tail -f /var/log/messages
浏览器打开虚拟ip访问：http://192.168.232.16:8080/ ，此时显示IP为192.168.232.134

服务器层的双机热备（比如服务器宕机、keepalived宕了）测试：

kill 192.168.232.134（master) 的keepalived进程 killall keepalived 134的日志信息如下：

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. Jun 11 18:03:10 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 192.168.232.16  
  2. Jun 11 18:03:15 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 192.168.232.16  
  3. Jun 11 19:30:44 localhost Keepalived: Terminating on signal  
  4. Jun 11 19:30:44 localhost Keepalived: Stopping Keepalived v1.2.2 (06/10,2014)  
  5. Jun 11 19:30:44 localhost Keepalived_vrrp: Terminating VRRP child process on signal  
  6. Jun 11 19:30:44 localhost Keepalived_healthcheckers: Terminating Healthchecker child process on signal  
 
Jun 11 18:03:10 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 192.168.232.16
Jun 11 18:03:15 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 192.168.232.16
Jun 11 19:30:44 localhost Keepalived: Terminating on signal
Jun 11 19:30:44 localhost Keepalived: Stopping Keepalived v1.2.2 (06/10,2014)
Jun 11 19:30:44 localhost Keepalived_vrrp: Terminating VRRP child process on signal
Jun 11 19:30:44 localhost Keepalived_healthcheckers: Terminating Healthchecker child process on signal

135的日志信息如下：

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. Jun 11 19:30:50 localhost Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.  
  2. Jun 11 19:30:50 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16  
  3. Jun 11 19:30:50 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.232.16 added  
  4. Jun 11 19:30:55 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16  
 
Jun 11 19:30:50 localhost Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
Jun 11 19:30:50 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16
Jun 11 19:30:50 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.232.16 added
Jun 11 19:30:55 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16

刷新http://192.168.232.16:8080/ ， 此时显示IP为192.168.232.135。
再次启动192.168.232.134的keepalived进程，192.168.232.134会自动接管成为master，192.168.232.135自动转为backup，从测试结果看，备机能成功接管，已经实现了热备。

应用层（web）的双机热备（比如nginx进程被意外kill、web端口不通）试验：

关闭192.168.232.134（master) 的nginx服务： service nginx stop
134的日志信息如下：

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. Jun 11 19:38:49 localhost Keepalived_vrrp: VRRP_Script(chk_http_port) failed  
  2. Jun 11 19:38:51 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Received higher prio advert  
  3. Jun 11 19:38:51 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATE  
  4. Jun 11 19:38:51 localhost Keepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.  
  5. Jun 11 19:38:51 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.232.16 removed  
 
Jun 11 19:38:49 localhost Keepalived_vrrp: VRRP_Script(chk_http_port) failed
Jun 11 19:38:51 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Received higher prio advert
Jun 11 19:38:51 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Entering BACKUP STATE
Jun 11 19:38:51 localhost Keepalived_vrrp: VRRP_Instance(VI_1) removing protocol VIPs.
Jun 11 19:38:51 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.232.16 removed

135的日志信息如下：

[plain] view plain copy print?在CODE上查看代码片派生到我的代码片
  1. Jun 11 19:38:52 localhost Keepalived_vrrp: VRRP_Instance(VI_1) forcing a new MASTER election  
  2. Jun 11 19:38:53 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE  
  3. Jun 11 19:38:54 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE  
  4. Jun 11 19:38:54 localhost Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.  
  5. Jun 11 19:38:54 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16  
  6. Jun 11 19:38:54 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.232.16 added  
  7. Jun 11 19:38:59 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16  
 
Jun 11 19:38:52 localhost Keepalived_vrrp: VRRP_Instance(VI_1) forcing a new MASTER election
Jun 11 19:38:53 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Jun 11 19:38:54 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Jun 11 19:38:54 localhost Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
Jun 11 19:38:54 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16
Jun 11 19:38:54 localhost Keepalived_healthcheckers: Netlink reflector reports IP 192.168.232.16 added
Jun 11 19:38:59 localhost Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth2 for 192.168.232.16

刷新http://192.168.232.16:8080/ ， 此时显示IP为192.168.232.135。
再次启动192.168.232.134的nginx进程，192.168.232.134会自动接管成为master，192.168.232.135自动转为backup，从测试结果看，备机能成功接管，已经实现了热备。

为什么主备的参数state都是MASTER，对的你没有看错确实要都设置成一样的，不然并不能实现我们想要的VIP漂浮的效果，我测试很久才发现的.state都设置成MASTER后，会根据priority的值大小竞争来决定谁是真正的MASTER，脚本检测也是在失败的时候会把权重减去相应的值，比如原来master（181）的priority=100，如果脚本检测到端口8088无法连接，就会priority-2=98，< S-B（150）的priority（99），此时 S-B（150） 将竞争成为master，这样就实现了web应用的热备。

如果以上实验都没有问题了，那么就该nginx负载均衡的配置了，配置修改参见如下：http://blog.csdn.NET/e421083458/article/details/30086413

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原文地址：https://www.cnblogs.com/kick/p/6274401.html