The art of the live upgrade - lessons from 10 years of evolving a live system

Klarna's main payment system has been running for over 10 years, serving millions of customers. The system has continuously evolved through live upgrades multiple times per week, without stopping nodes except for OS patching, Erlang VM upgrades, or hardware changes.

This talk will be about techniques, tools, mindset, and lessons learned during a decade of dynamic code loading.


Teaching practicioners about dynamic code loading techniques, tools, mindset, and war stories from a system that's been running for a decade.


Everyone running the Erlang VM in a live system.