nginx resolver数据缓存及解析超时时间参数


在配置nginx的resolver时，有两个与时间相关的参数。

一、valid

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Syntax: resolver address ... [valid=time] [ipv6=on|off];
Default:    —
Context:    http, server, location

如：
resolver 127.0.0.1 [::1]:5353 valid=30s;

valid flag means how long nginx will consider answer from resolver as valid and will not ask resolver for that period.
即DNS返回结果的缓存时间，在缓存有效时间内，nginx不会再次向DNS请求解析结果。

二、resolver_timeout

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Syntax: resolver_timeout time;
Default:    
resolver_timeout 30s;
Context:    http, server, location

resolve_timeout sets how long nginx will wait for anwser from resolver (DNS).
即nginx发起的DNS查询请求超时时间。

更多参考：