Worth 10% of the CNCF Certified Kubernetes Administrator (CKA) exam. CertClue has 10 questions on this objective.
What this objective covers
Volumes, Claims, and Storage Classes
Container filesystems disappear the moment a container is removed, so anything that must survive a restart needs a Volume. Kubernetes separates the storage itself, the PersistentVolume, from the request for storage, the PersistentVolumeClaim, so that application manifests can ask for a size and an access mode without knowing anything about the underlying disk technology. StorageClass then automates the whole thing so an administrator does not have to pre create a PersistentVolume for every claim.
Exam tip. A PVC stuck Pending almost always means no PersistentVolume satisfies its requested size, access mode, or StorageClass. Check kubectl get storageclass for a default class and kubectl describe pvc for the exact reason before assuming the storage backend itself is broken.
Practice questions
Free, with the answer and the reasoning. No account needed.
1. A PersistentVolumeClaim requests 10Gi of storage and specifies storageClassName: fast-ssd. No PersistentVolume matching that class currently exists, but the fast-ssd StorageClass has a provisioner configured. What happens to the PVC?
A. The PVC fails validation immediately and is rejected by the apiserver
B. The StorageClass's provisioner dynamically creates a matching PersistentVolume and binds it to the PVCcorrect
C. The PVC remains permanently unbound because no PersistentVolume was pre created by an administrator
D. The PVC automatically falls back to the default StorageClass
When a PVC references a StorageClass that has a provisioner defined, dynamic provisioning kicks in, the provisioner creates a new PersistentVolume that satisfies the PVC's request and size, and binds it automatically, no manual PV creation is required. The apiserver accepts the PVC as valid even before a PV exists, since binding can happen asynchronously. The PVC would only stay unbound indefinitely if there were no provisioner and no matching pre created PV. Since the PVC explicitly names fast-ssd as its storageClassName, it does not fall back to any default StorageClass.
Work the whole objective
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