Nginx四层负载均衡实践-优快云博客

nginx可以实现4层负载均衡。

软件四层负载均衡：
通过报文(数据包)中的目标地址和端口，加上分发机上的调度算法，决定最终选择哪个RIP。
LVS

软件七层负载均衡：
通过看客户端请求的具体内容(文字、图片、视频；网站交互)进行最终选择。

网络中常见的 SYN Flood 攻击。DOS。DDOS

nginx的4层负载均衡有2个条件：

1、版本在1.10以上

2、配置选项要有stream

[root@nginx-4c ~]# /usr/local/nginx/sbin/nginx -V 
nginx version: nginx/1.17.6
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-39) (GCC) 
built with OpenSSL 1.0.2k-fips  26 Jan 2017
TLS SNI support enabled
configure arguments: --prefix=/usr/local/nginx --user=www --group=www --with-http_stub_status_module --with-http_v2_module --with-http_ssl_module --with-http_sub_module --with-http_gzip_static_module --with-http_realip_module --with-stream

	--with-stream <--要这个选项

配置：

pid        logs/nginx.pid;
events {
    worker_connections  1024;
    use epoll;
}
》》》》》》》》》》》》》》》》》》》》》》》》
stream {
    upstream p_ssh {			
        hash    $remote_addr consistent;
        server  172.16.12.71:22;	
        server  172.16.12.72:22;
    }
    server {
        listen 24678;
        proxy_connect_timeout 3s;	
        proxy_timeout   10s;
        proxy_pass  p_ssh;
    }
}
》》》》》》》》》》》》》》》》》》》》》》》》

然后重启服务：
查端口，有24678那个新添加的端口

[root@nginx-4c nginx]# netstat -antlup | grep nginx
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      882/nginx: master p 
tcp        0      0 0.0.0.0:24678           0.0.0.0:*               LISTEN      882/nginx: master p

访问测试：

[root@localhost mnt]# ssh -p 24678 root@172.16.12.82

root@172.16.12.82's password: 
Last login: Sat Jan  4 00:59:11 2020 from 172.16.12.1
[root@chunk1 ~]# Connection to 172.16.12.82 closed by remote host.
Connection to 172.16.12.82 closed.

能够登录转发。

mysql

172.16.12.71

装个mysql

[root@chunk1 ~]# yum install mariadb-server -y 

[root@chunk1 ~]# systemctl restart mariadb
[root@chunk1 ~]# mysql

MariaDB [(none)]>  grant select on *.* to 'read'@'172.16.%' identified by '12345';
MariaDB [(none)]> flush privileges;

172.16.12.72

MariaDB [(none)]> grant all on *.* to 'write'@'172.16.%' identified by '12345';
MariaDB [(none)]> flush privileges;

stream {
    upstream mysql_read {
        hash    $remote_addr consistent;
        server  172.16.12.71:3306 weight=10 max_fails=3 fail_timeout=2s;
    }   
    upstream mysql_write {
        hash    $remote_addr consistent;
        server  172.16.12.72:3306 weight=10 max_fails=3 fail_timeout=2s;
    }   
    server {
        listen 3306;
        proxy_connect_timeout 3s;
        proxy_timeout   10s;
        proxy_pass  mysql_read;
    }
    server {
        listen 3307;
        proxy_connect_timeout 3s;
        proxy_timeout   10s;
        proxy_pass  mysql_write;
    }
}

重启查端口：
看到3306、3307，这两个是nginx启动的端口。

[root@nginx-4c nginx]# netstat -antlup | grep nginx
tcp        0      0 0.0.0.0:3307            0.0.0.0:*               LISTEN      882/nginx: master p 
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      882/nginx: master p 
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      882/nginx: master p

访问测试：

[root@client ~]# yum install -y mariadb

[root@client ~]# mysql -h 172.16.12.82 -P 3306 -u read -p12345
Welcome to the MariaDB monitor.  Commands end with ; or \g.

[root@client ~]# mysql -h 172.16.12.82 -P 3307 -u write -p12345
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 3