Hands-On Microservices with Kubernetes

Twelve factor app configuration

Heroku was one of the pioneers of cloud platform as a service. In 2011, they published the 12 factor methodology for building web applications. It's a pretty solid approach, and was very innovative at the time. It also happened to be the best way to build applications that could be deployed easily on Heroku itself.

For our purposes, the most interesting part of their website is the config section, which can be found at https://12factor.net/config.

In short, they recommend that web services and applications always store the configuration in environment variables. This is a safe but somewhat limited guideline. It means that the service has to be restarted whenever a configuration changes, and suffers from the ...