Code hot-loading is simple in Erlang. You recompile, make a fully qualified function call, and then enjoy. However, doing it the right (and safe) way is much more difficult.
A plethora of things can go wrong in practice.
In this chapter, we’ll explore the problems that hot code loading can bring and some principles that prove helpful to solve them. Then we’ll go through a practical demonstration of how to take an existing OTP release, upgrade it, and reload the new version of it while it runs with the help of OTP mechanisms, through appups and relups (application and release upgrades).
This chapter does not include all of the code used in the examples. Before you start this chapter, you might want ...