You may have heard of SaltStack's Reliable Asynchronous Event Transport (RAET) protocol. However, there's a very good chance you haven't heard much about it. To the average user, RAET may not seem like much. Salt commands haven't changed, output from the commands hasn't changed, and you certainly don't need to update your SLS files. In fact, if you've enabled RAET but haven't changed your workflow, you probably haven't noticed much of anything, which is by design. So what's the big deal? In fact, RAET introduces some interesting concepts that are new to the configuration-management game.

We will also take a look at the TCP transport that now ships with Salt. ZeroMQ already uses TCP, but this transport uses the protocol directly. Its introduction also came with the addition of a package to Salt called Tornado, which is an asynchronous programming library.

In this chapter, we'll cover the following topics: