Database migrations in Kubernetes - by Julien Singler
In the era of microservices and Kubernetes, managing database migrations has become more complex than ever. Traditional methods of running migrations during application startup are no longer sufficient.
This article explores various approaches to handling database migrations in a Kubernetes environment, with a focus on Golang-based solutions.
A naive implementation would be to run the code of the migration directly inside your main function before you start your server.
However, these could cause different issues like your migrations being slow and Kubernetes considering the pod didn’t start successfully and therefore killing it. You could run those migrations in a Go routine, but how do you handle failures then?
By using an initContainers in your Kubernetes Deployment, it will run the migration before the main application container starts. That’s a good first solution for when scaling is not a problem yet.
If the initContainer fails, the blue/green deployment from Kubernetes won’t go further and your previous pods stays where they are. It prevents having a newer version of the code without the planned migration.
