Following is proxy server show, too many connections from one client, this caused the proxy server hang, and the yarn web can't jump to web proxy.
Following is the AM which is abnormal, but proxy server don't know it is abnormal already, so the connections can't be closed, we should add time out support in proxy server to prevent this. And one abnormal AM may cause hundreds even thousands of connections, it is very heavy.
After i kill the abnormal AM, the proxy server become healthy. This case happened many times in our production clusters, our clusters are huge, and the abnormal AM will be existed in a regular case.
I will add timeout supported in web proxy server in this jira.