Great writeup and thanks for providing the code as well!

I think if I were to do this I'd probably do it the other way around. I'd introduce the new code first on a new node, add it to the load balancer, check it's healthy, and then remove the old node.

It allows a bit more growth for new functionality should it be needed. For example you can run a canary for an hour and check the error rates before promoting the deployment. Or you can rollback if the new code fails to start for some reason without needing to reload the previous application version first.

On the other hand, this works great if you want to keep the VPS more long lived by recycling it.