Azure Front Door 每秒多次轮询后端池状态

Question

在我们的网站中，我们有一条路线/health/xxx，您可以在其中检查网站的运行状况。在 xxx 部分，您可以添加任何内容，以便我们可以区分不同的轮询器。我们现在看到 Azure Front Door 每秒轮询站点几次。所有民意调查都返回 http 状态 200 并且网站正在运行。

前门轮询如此频繁的原因可能是什么？此外，我们还指定了使用 https 完成的探测，但它们是使用 http 完成的。

设置

日志

2020-02-04T08:31:14.788625531Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:14.889718097Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:15.056720867Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:15.108005604Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:15.694524409Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:16.228060671Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:16.531979272Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:16.566820933Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:16.588722534Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:17.950628116Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:17.992829110Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:18.337208799Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:18.392764355Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:18.421466287Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:18.529090784Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:18.743391272Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:18.777998932Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:18.962965185Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor
2020-02-04T08:31:19.251694816Z Request starting HTTP/1.1 GET http://ourappservice.azurewebsites.net/health/frontdoor

Answer 1

• HTTP or HTTPS is NOT HTTP/1.1

HTTP/1.1 显示 Web 应用程序的当前协议(protocol)。探测仅通过 https 完成。 HTTP/1.1 是 HTTP 或 HTTPS 协议(protocol)的规范。

更新1:

<小时/>

例如 - 请引用下面从 Fiddler 获取的 HTTPS 请求图片:

您可以观察到该请求使用 HTTPS 协议(protocol)，但属于 HTTP/1.1 protocol specification .

<小时/>

对于频繁探测 - 这是 Azure Front Door 的默认行为。它不断轮询运行状况探测器，以从后端池中决定最快/最好的服务器，它将路由它收到的第一个请求。

Front Door environments periodically sends a synthetic HTTP/HTTPS request to each of your configured backends. Front Door then uses responses from these probes to determine the "best" backends to which it should route real client requests.

引用号:Health Probes

<小时/>

For faster failovers, set the interval to a lower value. The lower the value, the higher the health probe volume your backends receive. For example, if the interval is set to 30 seconds with 90 Front Door environments or POPs globally, each backend will receive about 3-5 probe requests per second.

引用号:https://learn.microsoft.com/en-us/azure/frontdoor/front-door-backend-pool

<小时/>

并非所有边缘都会探测您的后端，只会探测距离接收请求最近的边缘。请参阅此视频以了解其详细工作原理。

希望这有帮助!