Foreword

Over my 20 years in computer networking, I have been lucky to work on a handful of popular, large-scale systems. If you had asked me in 2001, I would have told you my favorite project was AOL Instant Messenger. To scale to the size that we did in the early days, we had to create our own APIs for provisioning, security, and control over all aspects of the service--all aspects save the physical network, that is. This was a pain, but we lived with it as compute and storage needs were dynamic while network needs stayed reasonably static. In 2010, while working on what would become Microsoft Azure, it was clear that usage patterns have changed. Compute and storage have now been disaggregated, so it is more important than ever to have non-blocking connectivity and the ability to utilize any overlay technology required by the workload.

Within the last few years, we have seen quite a shift in thinking, from network device vendors adding APIs and Python scripting environments to their devices in the hope of them being driven programmatically. In this book, Eric Chou helps us gain a thorough understanding of interfacing with networks and network devices using Python, from interacting with a single device to large numbers of devices with complex automation using Ansible. Then, he takes us to my favorite topics of network monitoring and security, as well as an array of OpenFlow projects controlled through the Python-based Ryu SDN controller.

Eric and I worked together at Microsoft, where we built Microsoft DEMon, an Openflow-based network packet broker. Eric's deep understanding of Python and his love for automation show in every project we work on together. I have had the pleasure to see many of Eric's examples from this book used in real life and proven in actual projects. In Mastering Python Networking, Eric is adding some theory and a set of practical examples taken from real problems that he has solved.

Rich Groves

Director of R&D at A10 Networks