Book Image

Nginx Troubleshooting

By : Alexey Kapranov
Book Image

Nginx Troubleshooting

By: Alexey Kapranov

Overview of this book

Nginx is clearly winning the race to be the dominant software to power modern websites. It is fast and open source, maintained with passion by a brilliant team. This book will help you maintain your Nginx instances in a healthy and predictable state. It will lead you through all the types of problems you might encounter as a web administrator, with a special focus on performance and migration from older software. You will learn how to write good configuration files and will get good insights into Nginx logs. It will provide you solutions to problems such as missing or broken functionality and also show you how to tackle performance issues with the Nginx server. A special chapter is devoted to the art of prevention, that is, monitoring and alerting services you may use to detect problems before they manifest themselves on a big scale. The books ends with a reference to error and warning messages Nginx could emit to help you during incident investigations.
Table of Contents (15 chapters)
Nginx Troubleshooting
About the Author
About the Reviewers
Rare Nginx Error Messages

Configuring alerts

Although monitoring itself is a very broad term and as a job may include a lot of activities, there are basically two sides to what a web service monitoring constitutes. Graphing values from sensors is important as a tool to make strategic decisions based on visually apparent trends and also a post factum investigation and sometimes even as a forensics tool. The other side is alerting, which allows administrators to react to incidents as quickly as possible, preventing business consequences. All major monitoring solutions include alerting subsystems and even the toy monitoring script that we built earlier in this chapter is basically a simple alerter.

The http_stub_status module provides scarce information, but it can still be used to quickly react to incidents. These are some good values that can be used to detect unusual conditions requiring immediate attention:

  • The incoming request rate is a global indicator of the load to your website. Sudden spikes indicate a surge...