Vlastimil Holer is a systems engineer, with focus on automation. He has worked with Unix-like systems for more than a decade, and first used Puppet in 2008 while preparing and managing the growing deployment of the GoodData cloud BI on Amazon EC2. Currently, he works on the CERIT Scientific Cloud project at Masaryk University, where he manages and automates their computing, cloud, and storage infrastructure.

Jeroen Hooyberghs is an open source and Linux consultant, working for Open Future in Belgium. In this position as well as in his earlier roles in Linux system administration, he obtained technical expertise through a lot of open source solutions, such as Puppet. In 2014, he became a Puppet Certified Professional and Official Puppet Trainer. As a reviewer, he contributed to Mastering Puppet and Puppet Cookbook, Third Edition.

Michael J. Ladd is a senior manager of systems engineering at Leapfrog Online LLC of Evanston, Illinois. He has been working with Linux systems for more than 15 years, and has been using Puppet for over 5 years. In addition to wrangling computers, Michael enjoys writing music and working through an ever-growing list of books to read. He writes very occasionally at www.mjladd.com, and can be reached at <[email protected]>.

Stephen McNally received his MBA from Tennessee Technological University in 2013 with focus on management information systems. Stephen has experience in procuring, deploying, maintaining, administering, and decommissioning some of the world's fastest supercomputers. Most notably, his team deployed the first academic petascale supercomputer, Kraken. Stephen has IT experience in multiple industries, including automotive manufacturing, healthcare, and research computing. He oversees all aspects of HPC operations as the group leader for some of the world's brightest and most talented administrators and programmers.

Marcus Young recently graduated with a degree in computer science and mathematics, before getting involved in system administration and DevOps. He currently works in software automation using open source tools and technologies. His hobbies include playing ice hockey and brewing beer. He also enjoys hardware projects based on microcontrollers and single-board computers. He is currently working on Implementing Cloud Design Patterns for AWS.