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nginx + keepalived 双机热备

序

双机热备是指两台机器都在运行，但并非两台机器同时在提供服务。当提供服务的一台出现故障的时候，另外一台会马上自动接管并且提供服务，且切换的时间非常短。

keepalived的工作原理是VRRP——虚拟路由冗余协议。

测试环境如下：

	ip	vip
master	192.168.174.135	192.168.174.140
backup	192.168.174.137	192.168.174.140

nginx

安装

sudo apt-get install nginx

查找配置文件位置

sudo find / -name nginx.conf /etc/nginx/nginx.conf

修改配置文件（nginx.conf）

user www-data; worker_processes 4; pid /run/nginx.pid; events {  worker_connections 1024; } http {  sendfile on;  tcp_nopush on;  tcp_nodelay on;  keepalive_timeout 65;  types_hash_max_size 2048;  include /etc/nginx/mime.types;  default_type application/octet-stream;  access_log /var/log/nginx/access.log;  error_log /var/log/nginx/error.log;  server {   listen 80 default_server;   server_name test;   charset utf-8;   location / {   root html;   index index.html index.htm;   proxy_set_header X-Real_IP $remote_addr;   client_max_body_size 100m;   }  } }

文件/usr/share/nginx/html/index.html

在192.168.174.135上加上 <h1>Welcome to nginx! 135 </h1>

在192.168.174.137上加上 <h1>Welcome to nginx! ***137*** </h1>

启动

sudo service nginx start

关闭

sudo service nginx stop

keepalived

安装

下载keepalived-1.2.19.tar.gz

tar –zxvf keepalived-1.2.19.tar.gz cd keepalived-1.2.19 ./configure --prefix=/usr/local/keepalived make sudo make install

期间可能出现问题：

!!! OpenSSL is not properly installed on your system. !!!!!! Can not include OpenSSL headers files. !!!

解决

sudo apt-get install libssl.dev

建立软链接

sudo ln -s /usr/local/keepalived/sbin/keepalived /sbin/ sudo ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/ sudo ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

启动

sudo keepalived -D -f /usr/local/keepalived/etc/keepalived/keepalived.conf

关闭

sudo killall keepalived

配置（keepalived.conf）：

global_defs {  router_id NODEA } vrrp_instance VI_1 {  state MASTER   interface eth0  #监测网络接口   virtual_router_id 50  #主、备必须一样    priority 100    #优先级：主＞备  advert_int 1  authentication {   auth_type PASS #VRRP认证，主备一致   auth_pass 1111  #密码 } virtual_ipaddress {   192.168.174.140/24 #VRRP HA虚拟地址  } }

备用节点的配置

global_defs {    router_id NODEB } vrrp_instance VI_1 {  state BACKUP  interface eth0  virtual_router_id 50  priority 90   advert_int 1  authentication {   auth_type PASS   auth_pass 1111  }  virtual_ipaddress {  192.168.174.140/24  } }

测试

双击热备

两台机子均启动nginx和keepalived，浏览器各自访问

nginx + keepalived 双机热备

浏览器访问： http://192.168.174.140/ ，显示的是MASTER的页面。

nginx + keepalived 双机热备

同样用ip appr可以验证：

135 机器：

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo