Kubernetes: Up & Running: Dive into the Future of Infrastructure

by Kelsey Hightower

Instead, you can modify the set of labels on the sick Pod. Doing so will disassociate it from the ReplicaSet (and service) so that you can debug the Pod. The ReplicaSet controller will notice that a Pod is missing and create a new copy, but because the Pod is still running, it is available to developers for interactive debugging, which is significantly more valuable than debugging from logs.

Regardless of the reasons for staying put, this legacy server and service are not going to move into Kubernetes, but nonetheless it is still worthwhile to represent this server in Kubernetes. When you do this, you get to take advantage of all of the built-in naming and service discovery primitives provided by Kubernetes. Additionally, this enables you to configure all your applications so that it looks like the database that is running on a machine somewhere is actually a Kubernetes service. This means that it is trivial to replace it with a database that is a Kubernetes service.