Virtual storage pools provide a crucial layer of abstraction between Astra Trident's storage backends and Kubernetes' StorageClasses.
In essence, virtual storage pools act as an intermediary layer within Astra Trident, the open-source storage orchestrator for Kubernetes. This layer helps bridge the gap between the underlying physical or logical storage systems (backends) and the way Kubernetes requests storage (StorageClasses).
Understanding the Abstraction Layer
- Storage Backends: These represent the actual storage infrastructure managed by Astra Trident, such as NetApp ONTAP arrays, AWS EBS, Google Cloud Persistent Disks, etc. Each backend has its own capabilities and configurations.
- Kubernetes StorageClasses: These are Kubernetes resources that define classes of storage, specifying parameters like provisioner (Astra Trident), allowed topology, reclaim policy, volume binding mode, and specific parameters required by the provisioner (like performance tiers, redundancy levels, etc.). Developers request storage using StorageClasses without needing to know the details of the underlying hardware.
- Virtual Storage Pools: This layer sits between the two. Instead of mapping a StorageClass directly to a single, specific backend, virtual storage pools allow you to group capabilities from one or more backends.
Why Use Virtual Storage Pools?
The primary benefit of virtual storage pools is simplifying storage management in complex Kubernetes environments:
- Flexibility: Decouples StorageClasses from rigid backend configurations. You can modify backend configurations or add/remove backends without necessarily changing existing StorageClasses, as long as the capabilities are still represented in the virtual pools.
- Consistency: Allows defining standard tiers of storage (e.g., "fast-ssd", "archive-hdd") that map to the best available storage across multiple backends.
- Simplified Provisioning: Users requesting storage via a StorageClass linked to a virtual pool don't need to worry about which specific backend will fulfill the request; Astra Trident selects the most suitable one from the pool.
- Dynamic Mapping: Astra Trident can dynamically choose the most appropriate backend from the virtual pool based on the request parameters specified in the StorageClass.
By providing this abstraction, virtual storage pools make it easier to manage diverse storage resources and ensure consistent storage provisioning for applications running on Kubernetes.
