Arista Warrior

Chapter 6. Introduction to EOS

The operating system for Arista switches is called the Extensible Operating System, or EOS for short. Arista describes EOS as “...the interface between the switch and the software that controls the switch and manages the network.” This is sort of like Apple’s OS X operating system, in that what you see is actually a Unix shell—Unix is doing all the heavy lifting behind the scenes. Arista switches run Unix natively, but to make them easier for nonprogrammers to understand, EOS makes them look more like traditional (Cisco) networking devices.

The word extensible means “capable of being extended.” EOS was designed from the ground up to allow third-party development of add-ons. This is a first in the networking world, and is a big departure from traditional proprietary operating systems. This extensibility is shown in detail in Chapters 11, 28, and 29.

Arista is a big believer in open standards, and there are no proprietary protocols found in EOS. Even features such as MLAG and VARP, both Arista developments, use behaviors found in existing open-standard protocols, the details of which we will see later in Chapters 12 and 14.

Perhaps even more impressively, Arista allows the user to access the underlying Linux operating system and to even write Python scripts that can control the switch. This is a significant difference from other vendors who advertise that their switches run a derivative of Linux. While those switches may be based on Linux, you can’t get ...