Chapter 8: Migrations and Testing Your Infrastructure

So far, we have mostly been concerned with how feature management and LaunchDarkly can be used to deliver new functionality to the frontend experiences through rollouts and experiments. In this chapter, we will look at a different way in which feature management can be used on backend systems. When used in this way, feature flags can be used to help migrate entire systems and even offer the opportunity for new types of testing.

We will build on what we learned in Chapter 4, Percentage and Ring Rollouts, to understand how a migration can be performed. In that chapter, I touched upon some of the scenarios that will be looked at in greater detail within this chapter.

Many of the examples provided so far have helped you make relatively small changes to applications, especially when it comes to running experiments, but there are occasions where much larger architectural changes need to be made to systems. Feature management can...