What does OpenShift use to provide storage to Cloud Pak for Integration components?

OpenShift, which is built on Kubernetes, utilizes the Persistent Volume (PV) framework to provide storage to containerized applications like the components of Cloud Pak for Integration. A Persistent Volume is an abstraction for a piece of storage in the cluster, which is decoupled from the lifecycle of any individual pod. Cloud Pak for Integration components request this storage using a Persistent Volume Claim (PVC). This mechanism allows stateful applications to maintain their data across restarts, rescheduling, and node failures, by mounting a persistent storage resource that exists independently within the cluster.

A. Network attached storage: This is a specific type of storage technology (e.g., NFS) that can be used to back a Persistent Volume, but it is not the abstraction layer OpenShift itself uses.

B. Local disk storage: This storage is tied to a specific node and is generally not suitable for stateful applications, as data is lost if the pod is rescheduled to a different node.

D. Spectrum storage: This refers to a specific family of IBM storage products. While it can be integrated with OpenShift to provide storage, it is not the native OpenShift mechanism itself.

1. IBM Cloud Pak for Integration 2023.2 Documentation: In the "Storage considerations" section

it states

"Cloud Pak for Integration requires persistent storage

which must be provisioned before you install. ... You must create the persistent volumes before you deploy a Cloud Pak for Integration instance

or you can create a storage class that can provision storage dynamically." This directly confirms the use of Persistent Volumes.

Source: IBM Documentation

Cloud Pak for Integration 2023.2

"Storage considerations".

2. Red Hat OpenShift Container Platform 4.14 Documentation: The "Understanding persistent storage" chapter explains the core concept: "OpenShift Container Platform uses the Kubernetes persistent volume (PV) framework to allow cluster administrators to provision persistent storage for a cluster. Developers can use persistent volume claims (PVCs) to request PV resources without having specific knowledge of the underlying storage infrastructure."

Source: Red Hat OpenShift Container Platform 4.14 Documentation

"Storage > Understanding persistent storage".

3. Kubernetes Official Documentation: As OpenShift is a Kubernetes distribution

it shares the same core concepts. The documentation on Persistent Volumes states: "A PersistentVolume (PV) is a piece of storage in the cluster that has been provisioned by an administrator or dynamically provisioned using StorageClasses. ... A PersistentVolumeClaim (PVC) is a request for storage by a user."

Source: Kubernetes.io

"Concepts > Storage > Persistent Volumes".