DevOps Troubleshooting

Have you ever been responsible for a server and had something go wrong? Ever been in a situation where you didn’t know what was causing the problem or how to figure it out? I think any of us who develop code, work in quality assurance, or administer systems have had this sort of experience. Sometimes problems appear that were never covered in a class or training session. Experience is an amazing teacher, but gaining that experience can be intimidating and sometimes painful. This book gives anyone working in DevOps a bit of a head start.

DevOps Troubleshooting: Linux Server Best Practices starts with a discussion of best practices in troubleshooting. This lays a good foundation for the rest of the book and should be read right away. If you don’t already know how to narrow down the location or source of a problem, how to communicate with others who may be affected or who can assist, or even where to start when a problem arises, the first chapter gives a solid plan to help you out. Most of the content of this chapter will seem obvious to people with experience, but they were not obvious to us when we started, and this information would have saved most of us a few headaches. Ideas like favoring quick, simple tests over slow and complex one, favoring past solutions that are known to work, and most importantly, understanding how the systems work before doing anything are vital. I like the advice about using the internet, but carefully, and resisting rebooting as a cure-all (because it doesn’t help you find the cause of the problem).

The chapters that follow are each focused on a specific type of problem. They include discussions of tips, tricks, and tools for diagnosing, and fixing issues. There are chapters that cover server slowness due to CPU, RAM, and Disk I/O issues, boot problems, full or corrupt disk issues, network problems, DNS server issues, email problems, web server problems, and database problems. There is even a chapter on diagnosing common hardware problems.

Experienced Linux server gurus may pick up a trick or two, but it is those who are new to working with Linux servers who are most likely to benefit from this book, and benefit in significant ways. The book doesn’t cover how to use Linux or how to set up your server, but it covers exactly what the title of the book says it will cover. For this reason, I consider this a perfect second Linux book for anyone who is relatively new to any aspect of DevOps with Linux.

Disclosure: I was given my copy of this book by the publisher as a review copy. See also: Are All Book Reviews Positive?

The Healthy Programmer

I sit at a desk all day. I sit with my hands on a keyboard or mouse and my eyes fixed on a computer screen. This is a terrible thing to do to one’s body. I learned this first hand when, just over two years ago, I developed wrist and back pain so severe I nearly chose a different career. Instead, I talked to a doctor, read up on ergonomics and repetitive stress injuries, and made some significant changes to how I work.

I wish this book had existed back then, and better yet that I had read the book before the pain started. Even though I am healthy and doing well, I find that I must be vigilant. I get up and walk for a few minutes every hour. I take longer walks at least twice a day. I look away from the monitor frequently. Still, when I’m in the groove, it is easy to look up and realize that I have not changed my position for 3 hours. Those moments are far less frequent, and must be infrequent if I want to be able to do this sort of work the rest of my life. Same goes for you, and the sooner you realize it and adjust your work habits for the sake of your health, the better.

The Healthy Programmer: Get Fit, Feel Better, and Keep Coding is a book I recommend highly to all who work behind a desk all day, but it is especially written for programmers. While I spend more time writing documentation nowadays, my thinking patterns and my physical habits fall into the same category. This book spoke clearly to me and I think it will to anyone in a similar position.

The Healthy Programmer suggests a method of implementing changes to daily work and diet patterns that will be familiar to programmers. It is iterative, measured, and all-around Agile. You start by taking stock of where you want to go, what you want to see happen. Then, you measure how things are today and make small changes, one at a time, to your life and see how each affects the things you measured. As you get the hang of one thing and choose to incorporate it into your regular lifestyle, you measure something else and repeat the process.

We start with an introductory chapter. These lay the foundation for why some habits are good while others are not. Most of the facts are already known to us. Face it, programmer/computer engineer types are a pretty bright bunch. However, we don’t always choose to apply our knowledge, primarily because of how we have adapted ourselves to the pressures of the job. Once you get past the no-scare-tactic-or-hype discussion of habits and the well-cited using academic journals research behind what the book promotes, you find yourself wanting to do the things it discusses. It is kind of like that time you heard about a new toolkit available in a programming language you love that lets you implement a feature you have been dying to play with. You can’t wait to get started.

Topics covered in the book include walking, sitting vs standing, diet and nutrition, headaches and eye strain, back pain, wrist pain, exercise, getting up and out of your cube or home office, understanding fitness, and more. Everything comes with citations and balanced, scientific discussion that never gives in to hype or fad. You get advice that is backed up by doctors, scientists, nutritionists, and fitness professionals…and none of it sounds like the stuff you hear in the diet craze of the month or year. There are no vague promises, no unrealistic expectations, no fearmongering nor scare tactics. Just good information that is well presented and molded into a style of communication and plan for implementation that will be familiar to programmers.

This is a 200+ page book that can be easily skimmed over a weekend. Then, you can go back through it slowly over a period of months and let it help you be or become healthy and prevent, reduce, or eliminate pain. It is worth it.

Disclosure: I was given my copy of this book by the publisher as a review copy. See also: Are All Book Reviews Positive?

Mastering NGINX

Nginx is an http server intended for high traffic websites with a mind toward network scalability. I used NGINX as my primary web server for about 3 years. At the time, I hosted my sites on under-powered hardware that had little memory and had trouble keeping up with demand when I used Apache, but was able to keep this web site up and running the day one of my posts hit the front page of Digg (back when dinosaurs roamed the Earth and Digg was a really cool website). Back then, NGINX was still pretty new and most of the documentation was either in Russian, sporadic, or consisted of random posts on people’s blogs. It has been a couple of years since I upgraded my server to something beefier. At that time, I switched back to Apache, since I have used it for years and know it very well. That could change again, especially now that the official documentation for NGINX is much better, and because of today’s review book.

Mastering NGINX is by Dimitri Aivaliotis, a systems architect for a hosting provider and someone who uses NGINX daily. His experience shows in the quality and depth of the material. Unlike a different book on NGINX from the same publisher that I reviewed in 2010, Nginx HTTP Server, this book is well written and does not suffer from what I have come to call “The Packt Problem.” I hope this is a sign that Packt’s copy editing process has improved and that there is now a stronger commitment to offer titles that are worthy of being read because of the quality of the writing as well as the quality and uniqueness of the technical content.

Mastering NGINX is intended for experienced systems administrators and systems engineers, people who are familiar with using and administering *nix machines and configuring servers. This is not a beginner book. For me, that is a plus. It allows the author to get right down to business with NGINX.

We start with a short and typical installation chapter, complete with a discussion of modules that includes third-party modules and their benefits and risks. Installing using the package managers of several types of Linux distributions is covered along with compiling from source and the various flags and configure options available.

The next chapter jumps right in to the good stuff. Most of the NGINX materials I once used tell you what to change, but not why to change it. For a long time I was left wondering how to tell when to use specific configuration options, which files to find them in, and what the parameters are that I can use. The goal of this book is not to tell you what to do, but to describe these very things, so that in the end, you should be able to find and open an NGINX configuration file and edit it to fit your situation. Well done.

I was a little concerned when I realized that I was nearing the end of the chapter and still had some questions in my mind about some of the parameters and settings. Then I read this on page 40 in the chapter summary:

What we did not cover in this chapter are the configuration options provided by the various modules that may be compiled into your nginx binary. These additional directives will be touched upon through the book, as that particular module is used to solve a problem. Also absent was an explanation of the variables that NGINX makes available for its configuration. These too will be discussed later in this book. This chapter’s focus was on the basics of configuring NGINX.

Bravo! The author was thinking ahead, anticipated my concerns, and addressed them immediately at the point I had them.

The rest of the book gives deeper, more detailed information about specific uses for NGINX. Topics covered include using NGINX for serving mail, reverse proxying, setting up security, HTTP serving, including setting up your server for use with PHP (which is much easier now than when I wrote this outdated post), caching, tracking, and various sorts of troubleshooting. I was thrilled to see the appendices, especially the rewrite rule guide, as when I tried to do rewrites, I couldn’t find any good information (see my now-long-outdated post on the topic.

I was pleased to see how complete and clear the book is. Kudos to the author, the reviewers and editors, and the publisher. I recommend this book to anyone who uses NGINX or wants to do so.

Disclosure: I was given my copy of this book by the publisher as a review copy.

Ubuntu on a Mac

With every copy of Ubuntu Unleashed 2013 Edition we include a DVD of Ubuntu 12.10. This is similar to what we have done with past editions. The contents of the DVD are identical to and taken from the main Ubuntu download page. In the past, this disc has been sufficient to boot live or install on either a Windows machine or a Mac. However, this time around, anyone putting the disc in a Mac will find that the machine will not boot from the disc.

Bummer. We didn’t discover this until after the book was printed, the DVDs were created and attached, and the book shipped. When I read through the install documentation for Ubuntu while doing the editing for the new edition of the book, I failed to see any note of there being a problem. In fact, as I looked today (20 December 2012), there is still no note of any special needs when using Apple Mac hardware on or in the install instructions at

I have found that there is a different install DVD image available for 64 bit Mac that anyone can download from, but this is not mentioned anywhere else that I can find and is not available from the main download page. I found it by searching Google and discovering the problem is common and that a new iso was created to circumvent a Mac-specific issue (details below on the actual issue).

If you bought my book and own Mac hardware, I apologize for the inconvenience. The DVD attached to the book will not boot on your machine, but you can download the Mac image mentioned just above and it should work.

For those interested in the technical details of the problem, here is a high-level description.

In past years, computers used a BIOS, or Basic Input/Output System, to load some software necessary for the hardware to then read and load an operating system. The industry has been moving to the UEFI, or Unified Extensible Firmware Interface, which serves a similar purpose to a BIOS but communicates differently and with greater flexibility. Most UEFI software includes legacy support for BIOS services to ensure compatibility across a wide range of hardware. Linux supports UEFI, and as a result, so does Ubuntu.

Because the version of UEFI that is included with Mac hardware only has to support a very limited range of hardware, it does not include that BIOS legacy support (and perhaps other support). This means that Mac hardware using UEFI can not read the files from the disc that are needed to boot Ubuntu. This is a direct result of Apple making a decision to use only the parts of the UEFI standard that support their Apple hardware. While it is not my preference as a geek and tinkerer, it is a reasonable business decision as Apple seems to prefer to control the entire user experience so that everything will “just work” for their users. The downside is that it becomes difficult to use any hardware or software they do not produce or directly sanction. Booting any operating system that is not OS X on Mac hardware is a use case that Apple does not support, so it doesn’t work easily. The workaround is to download the Ubuntu-community-provided modified DVD image linked above and use it as it has received some modifications that enable the version of UEFI on this Mac hardware to recognize the DVD and allow Ubuntu to boot.

VMware Cookbook, second edition

VMware Cookbook

Just released.

I had the privilege to work with Ryan Troy for both the original and for this second edition of
VMware Cookbook
. With scores of step-by-step solutions, this cookbook helps you work with VMware ESXi in a wide range of network environments. You’ll not only learn the basics—how to pool resources from hardware servers, computer clusters, networks, and storage, and then distribute them among virtual machines—but also how to overcome the stumbling blocks you’ll encounter when you monitor systems, troubleshoot problems, and deal with security.

This expanded second edition covers recent advances in vCloud Director and vShield cloud security. Ideal for system administrators of any level, VMware Cookbook also includes valuable information to help you determine your virtualization needs.

ISBN-13: 978-1449314477