keepalived+nginx高可用实现方法示例

唐伯虎

1.keepalived介绍
keepalived最初是专为LVS负载均衡软件设计的，用来管理并监控LVS集群系统中各个服务节点的状态，后来又加入了实现高可用的VRRP功能。keepalived除了能够管理LVS软件外，还能支持其他服务的高可用解决方案。
keepalived通过VRRP协议实现高可用功能的。VRRP（Virtual Router Redundancy Protocol）虚拟路由冗余协议。VRRP出现的目的就是为了解决静态路由单点故障问题，它能保证当个别节点宕机时，整个网络可以不间断地运行。
2.keepalived高可用故障转移原理
keepalived高可用服务之间的故障转移，是通过VRRP来实现的。在keepalived服务工作时，主Master节点会不断地向备节点发送（多播的方式）心跳消息，用来告诉备Backup节点自己还活着。
当主节点发生故障时，无法给备节点发送心跳消息，如果备节点无法继续检测到来自主节点的心跳。就会调用自身的接管程序，接管主节点的IP资源和服务。当主节点恢复时，备节点又会释放主节点故障时自身接管的IP资源和服务，恢复到原来的备用角色
3.安装nginx
3.1.主节点（192.168.80.22）
3.1.1.安装编译工具和库文件

yum -y install make zlib zlib-devel gcc-c++ libtool openssl openssl-devel

3.1.2.安装pcre

#进入目录
cd /usr/local/develop/anginx
 
#上传安装文件并解压
tar -zxvf pcre-8.38.tar.gz
 
#进入安装目录
cd pcre-8.38
 
#检查配置
./configure
 
#编译、安装
make && make install
 
#查看pcre版本
pcre-config --version

3.1.3.安装nginx

#进入目录
cd /usr/local/develop/anginx

#上传安装文件，并解压
tar -zxvf nginx-1.8.1.tar.gz

#进入安装目录
cd nginx-1.8.1

#检查配置
./configure --prefix=/usr/local/develop/anginx/webserver/nginx --with-http_stub_status_module --with-http_ssl_module --with-pcre=/usr/local/develop/anginx/pcre-8.38

#编译安装
make && make install

#查看nginx版本
 /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v
--------------------------------------------------------
[root@hadoop02 webserver]# /usr/local/develop/anginx/webserver/nginx/sbin/nginx -v
nginx version: nginx/1.8.1

#配置nginx（检查）
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -t

#nginx管理命令
/usr/local/develop/anginx/webserver/nginx/sbin/nginx     # 启动 Nginx
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop     # 停止 Nginx
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reload    # 重新载入配置文件
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s reopen    # 重启 Nginx

3.1.4.nginx基础配置

vi nginx.conf
 
#user nobody;
worker_processes 1;

#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;

pid  logs/nginx.pid;


events {
  worker_connections 1024;
}


http {
  include  mime.types;
  default_type application/octet-stream;

  log_format main '$remote_addr - $remote_user [$time_local] "$request" '
       '$status $body_bytes_sent "$http_referer" '
       '"$http_user_agent" "$http_x_forwarded_for"';

  access_log logs/access.log main;

  sendfile  on;
  #tcp_nopush   on;

  #keepalive_timeout 0;
  keepalive_timeout 65;

  #gzip on;
  
  #添加tomcat列表，真实应用服务器都放在这
  upstream tomcat_pool{
  #server tomcat地址:端口号 weight表示权值，权值越大，被分配的几率越大;
  server 192.168.80.22:8080 weight=4 max_fails=2 fail_timeout=30s;
  server 192.168.80.22:8081 weight=4 max_fails=2 fail_timeout=30s;
  
  }

  server {
  listen  80;
  server_name tomcat_pool;

  #charset koi8-r;

  #access_log logs/host.access.log main;

  location / {
    #root  html;
    #index index.html index.htm;
    proxy_pass http://tomcat_pool;  #转向tomcat处理
    proxy_set_header  Host     $host;
    proxy_set_header  X-Real-IP  $remote_addr;
    proxy_set_header  X-Forwarded-For $proxy_add_x_forwarded_for;
  }

  #error_page 404     /404.html;

  # redirect server error pages to the static page /50x.html
  #
  error_page  500 502 503 504 /50x.html;
  location = /50x.html {
    root  html;
  }


}

3.2.备节点（192.168.80.21）
说明：安装方式同nginx主节点。
4.安装keepalived
4.1.主节点（192.168.80.22）

#安装keepalived
yum install keepalived -y

#启动keepalived服务
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在启动 keepalived：           [确定]
[root@hadoop02 anginx]# ps -ef |grep keepalived
root   15723   1 0 00:59 ?  00:00:00 /usr/sbin/keepalived -D
root   15724 15723 0 00:59 ?  00:00:00 /usr/sbin/keepalived -D
root   15725 15723 0 00:59 ?  00:00:00 /usr/sbin/keepalived -D
root   15731 15622 0 00:59 pts/1  00:00:00 grep keepalived
[root@hadoop02 anginx]#

#设置开机自启动
echo "/etc/init.d/keepalived start" >>/etc/rc.local

#关闭keepalived服务
/etc/init.d/keepalived stop

#编辑keepalived配置文件
vi /etc/keepalived/keepalived.conf

-----------------------------------------------------------
! 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 lb01
}

vrrp_instance VI_1 {
  state MASTER
  interface eth1
  virtual_router_id 55
  priority 150
  advert_int 1
  authentication {
  auth_type PASS
  auth_pass server123
  }
  virtual_ipaddress {
  192.168.80.100 dev eth1 label eth1:1
  }
}
...........................................................

关于配置说明：

【router_id】是路由标识，在一个局域网里面应该是唯一的
- 【vrrp_instance VI_1】{...}这是一个VRRP实例，里面定义了keepalived的主备状态、接口、优先级、认证和IP信息
- 【state】定义了VRRP的角色
- 【interface】定义使用的接口，这里我的服务器用的网卡都是eth1
- 【virtual_router_id】是虚拟路由ID标识，一组的keepalived配置中主备都是设置一致
- 【priority】是优先级，数字越大，优先级越大，
- 【auth_type】是认证方式
- 【auth_pass】是认证的密码
【virtual_ipaddress】｛...｝定义虚拟IP地址，可以配置多个IP地址，这里我定义为192.168.80.100，绑定了eth1的网络接口，虚拟接口eth1:1

4.2.备节点（192.168.80.21）

#安装keepalived
yum install keepalived -y

#启动keepalived服务
/etc/init.d/keepalived start
-------------------------------------------
[root@hadoop02 anginx]# /etc/init.d/keepalived start
正在启动 keepalived：           [确定]
[root@hadoop02 anginx]# ps -ef |grep keepalived
root   15723   1 0 00:59 ?  00:00:00 /usr/sbin/keepalived -D
root   15724 15723 0 00:59 ?  00:00:00 /usr/sbin/keepalived -D
root   15725 15723 0 00:59 ?  00:00:00 /usr/sbin/keepalived -D
root   15731 15622 0 00:59 pts/1  00:00:00 grep keepalived
[root@hadoop02 anginx]#

#设置开机自启动
echo "/etc/init.d/keepalived start" >>/etc/rc.local

#关闭keepalived服务
/etc/init.d/keepalived stop

#编辑keepalived配置文件
vi /etc/keepalived/keepalived.conf

-----------------------------------------------------------------
! 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 lb02
}

vrrp_instance VI_1 {
  state BACKUP
  interface eth1
  virtual_router_id 55
  priority 100
  advert_int 1
  authentication {
  auth_type PASS
  auth_pass server123
  }
  virtual_ipaddress {
  192.168.80.100 dev eth1 label eth1:1
  }
}
.............................................................

5.测试
5.1.启动主备节点的keepalived服务

#在节点一执行（192.168.80.22）
/etc/init.d/keepalived start
-------------------------------------
[root@hadoop02 anginx]# ps -ef |grep keepalived
root   15788   1 0 01:09 ?  00:00:00 /usr/sbin/keepalived -D
root   15790 15788 0 01:09 ?  00:00:00 /usr/sbin/keepalived -D
root   15791 15788 0 01:09 ?  00:00:00 /usr/sbin/keepalived -D
root   15807 15622 0 01:33 pts/1  00:00:00 grep keepalived
[root@hadoop02 anginx]#


#在节点二执行（192.168.80.21）
/etc/init.d/keepalived start
---------------------------------------
[root@hadoop01 ~]# ps -ef |grep keepalived
root   11542   1 0 01:30 ?  00:00:00 /usr/sbin/keepalived -D
root   11544 11542 0 01:30 ?  00:00:00 /usr/sbin/keepalived -D
root   11545 11542 0 01:30 ?  00:00:00 /usr/sbin/keepalived -D
root   11550 11512 0 01:33 pts/1  00:00:00 grep keepalived
[root@hadoop01 ~]#

5.2.通过虚ip访问服务
http://192.168.80.100/session-redis-demo/

5.3.停止主节点keepalived服务

#在节点一执行（192.168.80.22）
/etc/init.d/keepalived stop

#观察备节点变化
ip addr
-------------------------------------------
[root@hadoop01 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
  link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff
  inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1
  inet 192.168.80.100/32 scope global eth1:1
  inet6 fe80::250:56ff:fe38:e546/64 scope link 
  valid_lft forever preferred_lft forever
[root@hadoop01 ~]#

5.4.继续通过虚ip访问服务
http://192.168.80.100/session-redis-demo/

6.keepalived+nginx整合
说明：编写nginx守护脚本，如果nginx服务出现故障，则停止当前节点的keepalived服务。自动切换到备用节点。
6.1.编写nginx守护脚本

vi nginx_check.sh

--------------------------------------
#!/bin/bash
while true
do
if [ $(netstat -tlnp|grep nginx|wc -l) -ne 1 ]
then
  /etc/init.d/keepalived stop
fi
sleep 2
done

#给脚本授权
chmod u+x nginx_check.sh

#执行脚本
nohup /usr/local/develop/anginx/shell/nginx_check.sh &

6.2.停止主节点nginx服务

#停止主节点nginx服务
/usr/local/develop/anginx/webserver/nginx/sbin/nginx -s stop

#查找进程
[root@hadoop02 ~]# ps -ef |grep nginx
root   15915   1 0 01:51 ?  00:00:00 /bin/bash /usr/local/develop/anginx/shell/nginx_check.sh
root   16516 15753 0 01:54 pts/5  00:00:00 grep nginx
[root@hadoop02 ~]#

#观察备用节点变化【服务正常】
ip addr
--------------------------------------
[root@hadoop01 shell]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 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: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
  link/ether 00:50:56:38:e5:46 brd ff:ff:ff:ff:ff:ff
  inet 192.168.80.21/24 brd 192.168.80.255 scope global eth1
  inet 192.168.80.100/32 scope global eth1:1
  inet6 fe80::250:56ff:fe38:e546/64 scope link 
  valid_lft forever preferred_lft forever
[root@hadoop01 shell]#

#再次重新启动主节点nginx和keepalived服务
/usr/local/develop/anginx/webserver/nginx/sbin/nginx

/etc/init.d/keepalived start

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://www.cnblogs.com/itall/p/10913599.html

[Nginx] keepalived+nginx高可用实现方法示例

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