nginx proxy 代理解析成ipv6导致请求失败

nginx配置反向代理后偶尔会有error日志

2023/04/20 07:18:21 [error] 16202#16202: *158346 connect() to [2001:4860:4802:38]:443 failed (101: Network is unreachable) while connecting to upstream, client: 120.199.83.1, server: a.test.net, request: "GET /new/favicon.ico HTTP/1.1", upstream: "https://[2001:4860:4802:38]:443/new/favicon.ico", host: "a.test.net", referrer: "-"

查询资料发现需要禁用ipv6解析

添加resolver 8.8.8.8 ipv6=off valid=600s; 禁用ipv6解析有效期10分钟

    location / {
            resolver 8.8.8.8 ipv6=off valid=600s;
            proxy_set_header    X-Real-IP  $remote_addr;
            proxy_set_header    X-Forwarded-For  $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_pass https://a.test.net;
    }

nginx -s reload 发现没有作用

继续查询资料发现nginx在没有变量的配置中只在启动的时候解析一次域名

(https://trac.nginx.org/nginx/ticket/723)

(https://github.com/DmitryFillo/nginx-proxy-pitfalls)

继续修改成带变量的配置如下

    location / {
            set $endpoint a.test.net;
            resolver 8.8.8.8 ipv6=off valid=600s;
            proxy_set_header    X-Real-IP  $remote_addr;
            proxy_set_header    X-Forwarded-For  $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_pass https://${endpoint};
    }

重启生效