Hot code upgrades on the BEAM are awesome, but they're not a piece of cake. If you're also interested in the challenges of making them production safe, I gave a talk about this topic on CodeBEAM Sto earlier this year:
OP talks in the summary about the importance of understanding the process. It's very much true, but you need to understand not only the process your tooling provides, but also what's going on in the background and what hasn't been taken care for you by your tools. I'm afraid these things are rarely understood about hot upgrades, even by experienced Erlang engineers.
https://youtu.be/epORYuUKvZ0?si=gkVBgrX2VpBFQAk5
OP talks in the summary about the importance of understanding the process. It's very much true, but you need to understand not only the process your tooling provides, but also what's going on in the background and what hasn't been taken care for you by your tools. I'm afraid these things are rarely understood about hot upgrades, even by experienced Erlang engineers.