Chapter 1, Searching for Problems in Nginx Configuration, briefly describes the configuration language of Nginx and presents some of the corner cases and several techniques to search for problems.

Chapter 2, Searching for Problems in Log Files, describes the logging subsystem, log syntax, and what to look for when you troubleshoot. Nginx provides thorough logs of everything it does.

Chapter 3, Troubleshooting Functionality, the central chapter in this book, contains a list of steps you will make while investigating a problem. You will find the types of problems people generally encounter with their Nginx-powered web servers.

Chapter 4, Optimizing Website Performance, is dedicated to all things about performance. Starting with thorough explanation of the basic principles behind the Nginx event-driven processing model, it also touches on caching and even gives some advice on possible upstream optimization.

Chapter 5, Troubleshooting Rare Specific Problems, is devoted to studies of several real cases that you may face, from some of the simplest and easiest cases to fix to more problematic cases. The cases described might not be the most frequent, but they still provide valuable insight on the internals of the software and the methods of troubleshooting.

Chapter 6, Monitoring Nginx, is devoted to the abundance of tools available today that you may use for monitoring. No system is complete without good processes for the detection of emerging problems.

Chapter 7, Going Forward with Nginx, the short final chapter, provides a selection of directions you may choose for your further development as a specialist. The whole industry is very dynamic, and you should never settle.

Appendix, Rare Nginx Error Messages, provides a reference of interesting and not very common error messages that you might encounter in your log files.

Although modern versions of Nginx support Windows, this configuration is not considered production-ready. Most of the examples in this book will work on your Windows machines, but we still recommend having a Linux or FreeBSD server for experiments.

Nginx itself is pretty stable, so any version released since 2013 will suffice. Some of the newer features are only available in more recent versions, and those cases are marked in the book. We always recommend running modern Nginx from the stable line in production. As of the start of the year 2016, it is 1.8.1.

The book is for technical specialists who already use Nginx to serve web pages for their users. Whether you are an experienced system administrator or a new professional, this book will help you do your job in the most efficient way.

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The error_page directive installs a handler for an HTTP error based on the famous HTTP status codes."

A block of code is set as follows:

...
simple_command 4 "two";
# another_simple_command 0;

special_context {
    some_special_command /new/path;
    multiline_directive param {
        1 2 3 5 8 13;
    }
    include common_parameters;
}
...

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

Cache-Control:"max-age=1800"
Content-Encoding:"gzip"
Content-Type:"text/html; charset=UTF-8"
Date:"Sun, 10 Oct 2015 13:42:34 GMT"
Expires:"Sun, 10 Oct 2015 14:12:34 GMT"
Server:"nginx"
X-Cache:"EXPIRED"

Any command-line input or output is written as follows:

% sudo nginx -t
nginx: [emerg] unexpected end of file, expecting "}" in /etc/nginx/nginx.conf:1
nginx: configuration file /etc/nginx/nginx.conf test failed

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "You should have a way to reboot an otherwise unreachable server; every sane modern hosting provider has it, whether in the form of a simple menu item Reboot, such as in Amazon EC2 or a whole IPMI console access."

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