Keepalived配合Nginx搭建高可用服务器集群

2019独角兽企业重金招聘Python工程师标准>>>

系统

两台Nginx：

CentOS6.5 x86_64

两台tomcat：

CentOS6.5 x86_64

1.拓扑

机器IP	安装软件	角色	虚拟ip	描述
192.168.15.132	Nginx、keepalived	Nginx主机	192.168.15.135	反向代理到tomcat1和tomcat2
192.168.15.133	Nginx、keepalived	Nginx备机	主机挂了切换虚拟ip 192.168.15.135	反向代理到tomcat1和tomcat2
192.168.15.128	Tomcat	Tomcat1	无
192.168.15.30	Tomcat	Tomcat2	无

IP地址

nginx(主LB):192.168.15.132

nginx(备LB):192.168.15.133

VIP地址:192.168.15.135

Real1的IP:192.168.15.128

Real2的IP:192.168.15.30

2.安装keepalived和nginx

在两台nginx服务器张安装keepalived：

wget http://www.keepalived.org/software/keepalived-1.2.15.tar.gz

tar -zxvf keepalived-1.2.15.tar.gz
cd keepalived-1.2.15
./configure --sysconf=/etc/  --with-kernel-dir=/usr/src/kernels/2.6.32-573.8.1.el6.x86_64
make && make install
ln -s /usr/local/sbin/keepalived  /sbin/  

ln -s这一步很重要

不执行ln -s会报错“Starting keepalived: /bin/bash: keepalived: command not found”

service keepalived start

上述步骤也可以直接通过yum –y install keepalived 来代替，不同安装方式而已，不是重点

3.配置keepalived和nginx

二台Nginx上keepalived.conf配置文件如下

user  nobody;
worker_processes  1;
error_log  /usr/local/nginx/logs/error.log notice;
pid        /usr/local/nginx/logs/nginx.pid;
worker_rlimit_nofile 51200;
events {
    use epoll;
    worker_connections  51200;
}
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;
    server_names_hash_bucket_size 128;
    client_header_buffer_size 32k;
    large_client_header_buffers 4 32k;
    client_max_body_size 8m;
    sendfile        on;
    tcp_nopush     on;
    server_tokens off;
    keepalive_timeout  60;
    fastcgi_connect_timeout 300;
    fastcgi_send_timeout 300;
    fastcgi_read_timeout 300;
    fastcgi_buffer_size 64k;
    fastcgi_buffers 4 64k;
    fastcgi_busy_buffers_size 128k;
    fastcgi_temp_file_write_size 128k;
    gzip  on;
    upstream backend
    {
    server 192.168.15.128;
    server 192.168.15.130;
    }
    server {
        listen       80;
        server_name  192.168.15.135;
        location / {
            root   html;
            index  index.php index.html index.htm;
            proxy_redirect off;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            #后端的Web服务器可以通过X-Forwarded-For获取用户真实IP
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_pass http://backend;
        }
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
         
        location /nginx_status {
            stub_status on; 
            auth_basic "NginxStatus";
            auth_basic_user_file /usr/local/nginx/htpasswd;
            #allow 127.0.0.1;
            #deny all;
        }
        location ~* \.(ini|docx|txt|doc|pdf)$ {
        #禁止访问文档性文件
        root /usr/share/nginx/html;
        deny all;
        }
        location ~ .*\.(gif|jpg|jpeg|png|bmp|swf|js|html|htm|css)$ {
        root /home/image;
        proxy_store on;
        proxy_store_access user:rw group:rw all:rw;
        proxy_temp_path /home/image;
        if ( !-e $request_filename) {
           proxy_pass  http://backend;
        }
    }
}
}

配置完成后分别service keepalived start启动｡检验keepalived配置是否成功

两台keepalived的配置如下：可以看出两者之间的区别仅仅是主备的权重不同，主为100备为66，其余一些有作用的配置已经用红色标注

主：

global_defs {
   notification_email {
     [e-mail]
   }
   notification_email_from [e-mail] 
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_MASTER
}
vrrp_script chk_http_port {
script "/usr/local/src/check_nginx_pid.sh"
interval 2                           #（检测脚本执行的间隔）
weight 2
}
vrrp_instance VI_1 {
   #state MASTER
    state BACKUP
    nopreempt                       
    #设置非抢占模式时，修改“state MASTER”为“state BACKUP”，添加“nopreempt“
    interface bond0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
}
track_script {
chk_http_port            #（调用检测脚本）
}
    virtual_ipaddress {
        192.168.15.135
    }
}

备： 

global_defs {
   notification_email {
     [e-mail]
   }
   notification_email_from [e-mail] 
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_BACKUP
}
vrrp_script chk_http_port {
script "/usr/local/src/check_nginx_pid.sh"
interval 2                           #（检测脚本执行的间隔）
weight 2
}
vrrp_instance VI_1 {
    state BACKUP
    interface bond0
    virtual_router_id 51
    priority 66
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
}
track_script {
chk_http_port            #（调用检测脚本）
}
    virtual_ipaddress {
        192.168.15.135
    }
}

以下是针对nginx状态进行检测的脚本，第一次nginx服务死掉时，会重新启动，如果Nginx服务无法正常启动，则杀掉keepalived进程

vim  /usr/local/src/check_nginx_pid.sh

#!/bin/bash
A=`ps -C nginx --no-header |wc -l`        
if [ $A -eq 0 ];then                            
      /usr/local/nginx/sbin/nginx        
      if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then  
              killall keepalived                    
      fi
fi

Ok，开始nginx负载均衡测试，停掉其中一台的任何服务，不影响整个系统的运作｡

4.测试

依次启动两个tomcat=》启动两个nginx=》启动两个keepalived，查看主机上是否有虚拟ip 192.168.15.135

在192.168.15.128和192.168.15.30上分别解压修改tomcat的index页面：

vi webapps/ROOT/index.jsp

修改页面html部分

<html>
    <head>
    </head>
    <body>
SessionID:<%=session.getId()%>
<br/>
SessionIP:<%=request.getServerName()%>
<br/>
<h1>tomcat1 page</h1>
</body>
</html>

这样可以通过访问index来判断访问是不是轮询的

通过虚拟ip访问nginx，看页面是不是轮询两个tomcat

将主机的nginx进程kill掉，看看vip是不是切换到备机器上了

访问虚拟ip是不是还能轮询访问tomcat

转载于:https://my.oschina.net/liuyuantao/blog/1507432