"Decoding 'connect() failed (111)' Error in Reverse Proxies like Nginx and Troubleshooting Steps"

The error message "*10594787 connect() failed (111: connection refused) while connecting to upstream" typically occurs in a reverse proxy setup, such as when you are using Nginx or other similar software. This indicates that the proxy server tried to establish a connection with an upstream server (like your application server), but the upstream server refused the connection. Here's what this error means: 1. Connection Refused (Error 111): This is a standard TCP error code indicating that the destination host actively refused the connection attempt. It could mean that the service on the upstream server isn't running, is not listening on the expected port, or has reached its maximum connection limit. 2. Upstream: In the context of reverse proxies like Nginx, "upstream" refers to the backend servers where the actual applications or services run. When a client request comes to Nginx, it forwards the request to one of these upstream servers. Steps to troubleshoot: - Ensure that the upstream server is up and running. - Check that the service (e.g., your web application) is configured to listen on the correct IP address and port mentioned in your Nginx configuration file. - If there are firewall rules in place, ensure they allow traffic from the proxy server to the upstream server on the specified port. - Confirm that the upstream server hasn't exceeded its connection limit or resource constraints that might cause it to reject new connections. - Double-check the Nginx configuration for any errors; sometimes, incorrect server definitions or proxy_pass directives can lead to connection issues. Once you've verified and rectified the underlying issue, restart Nginx to apply the changes and test the connection again. ######[AI写代码神器 | 354点数解答 | 2024-02-18 09:55:28]