Part 3 Application configuration and storage
Part 3 focuses on how to use the Kubernetes API to configure your applications and attach both transient and persistent storage to them.
Chapter 8 shows you how to provide configuration to your application using command-line arguments and environment variables, whether specified directly in your object manifests or sourced from other Kubernetes objects. You’ll learn about the ConfigMap object, which stores nonsensitive configuration data, and the Secret object, designed for sensitive information such as private keys, authentication tokens, and passwords.
In chapter 9, you’ll add disk volumes to your pods and mount them into their containers. You’ll learn how to persist files across container restarts, share files between containers in the same pod, access a node’s filesystem from within a container, and provide data from a ConfigMap, a Secret, or even the pod’s own metadata via mounted files.
Chapter 10 builds on this by introducing persistent storage. You’ll learn the roles of a PersistentVolume and a PersistentVolumeClaim, the difference between static and dynamic provisioning, and how Kubernetes handles both node-local and network-attached storage. You’ll also explore the distinction between long-lived and ephemeral persistent volumes and learn how to create volume snapshots to clone or restore a volume to a previous state.