How to Solve "(110: Connection timed out) while reading response header from upstream" Nginx Error?

Published July 05, 2024

Problem: Nginx Connection Timeout Error

The "(110: Connection timed out) while reading response header from upstream" error in Nginx happens when the server doesn't get a quick response from an upstream service. This problem can affect web applications, causing slow content delivery. Users might see slow page loads or be unable to access parts of a website when this error occurs.

Solutions for the Nginx Upstream Timeout Issue

Adjusting Nginx Timeout Settings

To fix the Nginx upstream timeout issue, you can change the timeout settings. Modify the proxy_read_timeout directive in your Nginx config. This setting controls how long Nginx waits for a response from the upstream server. Increasing this value gives the upstream server more time to respond before Nginx ends the connection.

You can also set the proxy_connect_timeout and proxy_send_timeout directives. The proxy_connect_timeout sets how long Nginx waits to connect with the upstream server. The proxy_send_timeout sets how long Nginx waits while sending a request to the upstream server.

Optimizing Backend Server Performance

You can also improve your backend servers' performance. Start by fixing slow response times from upstream servers. This may include making database queries faster, caching data, or adding more server resources to handle higher loads.

Making API and PHP processing faster can also reduce timeout errors. You can use opcode caching for PHP, make your application code better, and design APIs more efficiently. These steps can lead to faster response times and fewer timeout issues.

Advanced Troubleshooting for Nginx Controller Errors

Investigating Nginx Ingress Controller Issues

When you face Nginx upstream timed out errors, check the Nginx Ingress Controller. Review recent config changes. Look at your Nginx configuration files for changes that might cause the timeout issue. Focus on settings for upstream servers, load balancing, and proxy configurations.

Check the Nginx process status. Use the command line to see if the Nginx service is running. Look for error messages in the Nginx error logs that might explain the timeout problem.

Resolving Nginx Reload Triggers

Frequent Nginx reloads can lead to timeout errors. Find the causes of these reloads by checking your system logs for patterns or events that trigger them. Common causes include config changes, certificate updates, or automated deployments.

To address backend reload needs, review your application deployment method. Consider using rolling updates or blue-green deployments to reduce downtime and the need for frequent Nginx reloads. Also, improve your backend services to handle requests faster, lowering the chance of timeouts during reloads.

Alternative Approaches to Resolve the Timeout Error

Implementing Nginx Keepalive Settings

Configuring keepalive_timeout in Nginx can help reduce timeout errors. This setting determines how long Nginx keeps idle connections open. Set a value based on your server's needs and traffic patterns. A typical starting point is 65 seconds:

keepalive_timeout 65;

Using proxy_http_version 1.1 and proxy_set_header connection helps maintain connections between Nginx and upstream servers. Add these directives to your Nginx configuration:

proxy_http_version 1.1;
proxy_set_header Connection "";

These settings allow Nginx to reuse connections, reducing the creation of new ones and possibly decreasing timeout errors.

Examining SSL Certificate Loading

Verifying TLS certificate validity is important when troubleshooting timeout errors. Check that your SSL certificates are up-to-date and installed correctly. Use OpenSSL to verify the certificate's expiration date and validity:

openssl x509 -in certificate.crt -text -noout

If you encounter certificate loading issues, check the Nginx error logs for SSL-related errors. Common problems include incorrect file permissions, mismatched private keys, or incomplete certificate chains. Make sure the certificate files are readable by the Nginx process and that the full certificate chain is provided if needed.

To troubleshoot certificate loading issues:

  1. Verify file permissions of SSL-related files.
  2. Check that the certificate and private key match.
  3. Confirm that the full certificate chain is present if needed.
  4. Review Nginx SSL configuration directives for mistakes.