[CentOS 7-NGINX-DNS负载平衡

Question

使用NGINX在CentOS 7上构建DNS负载平衡服务。曾在Ubuntu上进行此工作，但开始收到参差不齐的结果，并希望转向centos。我遇到的问题是端口53阻塞，我似乎无法弄清楚是什么。这是有道理的，因为Ubuntu具有相同的问题，但易于修复。只需关闭正在运行的端口53上运行的服务即可。我一直在挖掘和搜寻我的屁股，但似乎找不到烟枪。

默认情况下，什么服务在端口53上保留端口53？

非常感谢您的帮助。谢谢。

● nginx.service - The nginx HTTP and reverse proxy server
   Loaded: loaded (/usr/lib/systemd/system/nginx.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/nginx.service.d
           └─nginx.conf
   Active: failed (Result: exit-code) since Wed 2019-12-18 16:11:02 EST; 13min ago
  Process: 1863 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=1/FAILURE)
  Process: 1861 ExecStartPre=/usr/bin/rm -f /run/nginx.pid (code=exited, status=0/SUCCESS)

Dec 18 16:11:02 dnsload.dutil.com systemd[1]: Starting The nginx HTTP and reverse proxy server...
Dec 18 16:11:02 dnsload.dutil.com nginx[1863]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
Dec 18 16:11:02 dnsload.dutil.com nginx[1863]: nginx: [emerg] bind() to 0.0.0.0:53 failed (13: Permission denied)
Dec 18 16:11:02 dnsload.dutil.com nginx[1863]: nginx: configuration file /etc/nginx/nginx.conf test failed
Dec 18 16:11:02 dnsload.dutil.com systemd[1]: nginx.service: Control process exited, code=exited status=1
Dec 18 16:11:02 dnsload.dutil.com systemd[1]: nginx.service: Failed with result 'exit-code'.
Dec 18 16:11:02 dnsload.dutil.com systemd[1]: Failed to start The nginx HTTP and reverse proxy server.

stream {
    upstream dns_servers {
        least_conn;
        zone dns_mem 64k;
        server 192.168.100.240:53 fail_timeout=60s;
        server 192.168.100.241:53 fail_timeout=60s;
        server 192.168.100.239:53 fail_timeout=60s;
    }

    server {
        listen 53  udp;
        listen 53; #tcp
        proxy_pass      dns_servers;
        error_log       /var/log/nginx/dns.log debug;
        proxy_responses 1;
        proxy_timeout   1s;
    }
}

Answer 1

PowerDNS DNSDISThttps://dnsdist.org/

发现这真是太神奇了！ DNS负载平衡解决方案！