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Due to the modification of the server configuration on the upstream, Max is added_ fails,fail_ The three parameters of timeout and weight result in a large number of errors of the following types in nginx error log.

First of all, the problem is related to the client. The client is accessed by HTTP. Then, the problem is that there is a problem in the connection and interaction between nginx and the back-end API. After checking the configuration of nginx, there is no problem in the configuration

Looking at the explanation of the error, we can get the result that there is no server that can provide services in the upstream. However, I can directly access the back-end server, which proves that the server is available

Finally, find the document, and find that the problem is that the business requires to keep the session, but nginx does not keep the session to the API. Of course, nginx can not find the back-end available server, and it will report no live upstream

Modify the configuration of nginx