Keepalived+Nginx 高可用集群（主从模式）

Keepalived+Nginx 高可用集群（主从模式）

1.集群架构图

说明：Keepalived机器同样是nginx负载均衡器。

1）实验环境准备（此处都是使用的centos7系统）

# cat /etc/redhat-release 
CentOS Linux release 7.4.1708 (Core)

在所有节点上面进行配置

#关闭防火墙
systemctl stop firewalld         
#关闭selinux，重启生效
sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/sysconfig/selinux    
#关闭selinux，临时生效    
setenforce 0      
#时间同步  　　　　　　　　
ntpdate 0.centos.pool.ntp.org    
#安装nginx
yum install nginx -y        　　　

安装工具包，否则会影响后面语句命令找不到

yum install -y net-tools

2）配置后端web服务器（两台一样）

echo "`hostname` `ifconfig ens33 |sed -n 's#.*inet \(.*\)netmask.*#\1#p'`" > /usr/local/nginx/html/index.html

#编辑配置文件
vi /usr/local/nginx/conf/nginx.conf        

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
include /usr/share/nginx/modules/*.conf;
events {
    worker_connections 1024;
}
http {
    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  /var/log/nginx/access.log  main;
    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;
    include /etc/nginx/conf.d/*.conf;
    server {
        listen       80;
        server_name  www.mtian.org;
        location / {
            root         /usr/share/nginx/html;
        }
    access_log    /var/log/nginx/access.log main;
    }
}

 启动nginx

cd usr/local/nginx/sbin
./nginx

3）配置LB服务器（两台都一样）

# vi /usr/local/nginx/conf/nginx.conf
#user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
include /usr/share/nginx/modules/*.conf;
events {
    worker_connections 1024;
}
http {
    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  /var/log/nginx/access.log  main;
    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;
    include /etc/nginx/conf.d/*.conf;
    upstream backend {
    server 192.168.1.33:80 weight=1 max_fails=3 fail_timeout=20s;
    server 192.168.1.34:80 weight=1 max_fails=3 fail_timeout=20s;
    }
    server {
        listen       80;
        server_name  www.mtian.org;
        location / {
        proxy_pass http://backend;
        proxy_set_header Host $host:$proxy_port;
        proxy_set_header X-Forwarded-For $remote_addr;
        }
    }
}

启动nginx

cd usr/local/nginx/sbin
./nginx

4）在测试机（192.168.1.35）上面添加host解析，并测试lb集群是否正常。（测试机任意都可以，只要能访问lb节点。）

[root@node01 ~]# vi /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.1.32    www.mtian.org
192.168.1.31    www.mtian.org

// 测试时候轮流关闭lb1 和 lb2 节点，关闭后还是能够访问并看到轮循效果即表示 nginx lb集群搭建成功。
[root@node01 ~]# curl www.mtian.org
web01 192.168.1.33  
[root@node01 ~]# curl www.mtian.org
web02 192.168.1.34  
[root@node01 ~]# curl www.mtian.org
web01 192.168.1.33  
[root@node01 ~]# curl www.mtian.org
web02 192.168.1.34  
[root@node01 ~]# curl www.mtian.org
web01 192.168.1.33  
[root@node01 ~]# curl www.mtian.org
web02 192.168.1.34

5）上面步骤成功后，开始搭建keepalived，在两台 lb节点上面安装keepalived（也可以源码编译安装、此处直接使用yum安装）

yum install keepalived -y

6）配置 LB-01节点

[root@LB-01 ~]# vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
    [email protected]
   }
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
    192.168.1.110/24 dev ens33 label ens33:1
    }
}

[root@LB-01 ~]# systemctl start keepalived     //启动keepalived
[root@LB-01 ~]# systemctl enable keepalived    //加入开机自启动

[root@LB-01 ~]# ip a    //查看IP，会发现多出了VIP 192.168.1.110
......
2: ens33: mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:94:17:44 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.31/24 brd 192.168.1.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet 192.168.1.110/24 scope global secondary ens33:1
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe94:1744/64 scope link
       valid_lft forever preferred_lft forever
......

7）配置 LB-02节点

[root@LB-02 ~]# vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
    [email protected]
   }
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
    192.168.1.110/24 dev ens33 label ens33:1
    }
}

[root@LB-02 ~]# systemctl start keepalived        //启动keepalived
[root@LB-02 ~]# systemctl enable keepalived    //加入开机自启动

[root@LB-02 ~]# ifconfig   //查看IP，此时备节点不会有VIP（只有当主挂了的时候，VIP才会飘到备节点）
ens33: flags=4163  mtu 1500
        inet 192.168.1.32  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::20c:29ff:feab:6532  prefixlen 64  scopeid 0x20
        ether 00:0c:29:ab:65:32  txqueuelen 1000  (Ethernet)
        RX packets 43752  bytes 17739987 (16.9 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4177  bytes 415805 (406.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
......

8）在测试机器上面访问 Keepalived上面配置的VIP 192.168.1.110

[root@node01 ~]# curl 192.168.1.110
web01 192.168.1.33  
[root@node01 ~]# curl 192.168.1.110
web02 192.168.1.34  
[root@node01 ~]# curl 192.168.1.110
web01 192.168.1.33  
[root@node01 ~]# curl 192.168.1.110
web02 192.168.1.34

//关闭LB-01 节点上面keepalived主节点。再次访问
[root@LB-01 ~]# systemctl stop keepalived
[root@node01 ~]#
[root@node01 ~]# curl 192.168.1.110
web01 192.168.1.33  
[root@node01 ~]# curl 192.168.1.110
web02 192.168.1.34  
[root@node01 ~]# curl 192.168.1.110
web01 192.168.1.33  
[root@node01 ~]# curl 192.168.1.110
web02 192.168.1.34

如果ping不通VIP，在已经关闭防火墙和selinux情况下， 原因很可能是开启了vrrp_strict，将这行注释掉。

关闭后重新即可。

systemctl restart keepalived