Hardware abstraction involves the creation of a programming layer that allows the computer operating system to interact with hardware devices at a general rather than detailed level. This layer involves logical code implementation that avails the hardware to any software program. For storage devices, abstraction provides a uniform interface for users accessing shared storage, concealing the hardware’s implementation from the operating system. This allows software running on user machines to get the highest possible performance from the storage devices. It also allows for device-independent programs since storage hardware abstraction enables device drivers to access each storage device directly.
Kubernetes is, by nature, infrastructure agnostic, for that it relies on plugins and volume abstractions to decouple storage hardware from applications and services. On the other hand, containers are ephemeral, and immediately lose data when they terminate. Kubernetes persists data created and processed by containerized applications on Physical Storage devices using Volumes and Persistent Volumes. These abstractions connect to storage hardware through various types of Hardware Abstraction Layer (HAL) implementations. Two commonly used HAL storage implementations for Kubernetes clusters are Container Attached Storage (CAS) and Software Designed Storage (SDS).