问题
We have SignalR Core running in IIS and the connections are not being closed over time.
This results in a 503 error:
HTTP Error 503.2 - Service Unavailable
The serverRuntime@appConcurrentRequestLimit setting is being exceeded.
When recycling the apppool the Current Connections will drop to 0 and then back up to around 50 (as actual clients reconnect). Over the course of a day it can easily reach 2000. Not every connection is leaking - the number does decrease but trends upwards over time.
Latest .NET Core 3.1 is installed.
回答1:
We are using Argo Tunnel which creates a tunnel from our webserver to the Cloudflare network.
Turns out it was an out of date cloudflared executable.
The version we were running was from 5/2019 and updating to the new version from 12/2019 has fixed the problem. In fact when stopping the cloudflare service all the connections instantly dropped away.
来源：https://stackoverflow.com/questions/60083256/signalr-core-connections-not-being-closed-and-bringing-down-iis