Welcome to our 10 Day Kubernetes interview session focusing on Kubernetes, a powerful container orchestration platform. Today Day 6, we'll focus on Kubernetes Storage: Kubernetes Persistent Volumes and Persistent Volume Claims
Interviewer: Can you explain what Persistent Volumes (PVs) and Persistent Volume Claims (PVCs) are in Kubernetes?
Candidate: Persistent Volumes (PVs) in Kubernetes are storage resources that are provisioned by an administrator and exist independently of any Pod that might use them. They act as an abstraction layer between storage and Pods, providing a way for administrators to dynamically provision storage resources. Persistent Volume Claims (PVCs), on the other hand, are requests made by Pods for storage resources. They allow Pods to consume storage without needing to know the details of the underlying storage implementation.
Interviewer: How do you define a Persistent Volume in Kubernetes?
Candidate: To define a Persistent Volume in Kubernetes, you typically create a YAML file that describes the characteristics of the storage, such as the volume type, size, access mode, and the storage backend. You then apply this YAML file using
kubectl apply -f {codeBox}Interviewer: How does a Pod access a Persistent Volume in Kubernetes?
Candidate: A Pod accesses a Persistent Volume by making a Persistent Volume Claim (PVC). The Pod specifies the desired storage in the form of a PVC in its YAML definition. Kubernetes then binds the PVC to a suitable PV that satisfies the PVC's requirements, and mounts the PV into the Pod's containers.
Interviewer: What are the different access modes for Persistent Volumes in Kubernetes?
Candidate: The access modes for Persistent Volumes in Kubernetes are:
- ReadWriteOnce (RWO): The volume can be mounted as read-write by a single node.
- ReadOnlyMany (ROX): The volume can be mounted read-only by many nodes.
- ReadWriteMany (RWX): The volume can be mounted as read-write by many nodes simultaneously.
Interviewer: How do you configure dynamic provisioning of Persistent Volumes in Kubernetes?
Candidate: To enable dynamic provisioning of Persistent Volumes in Kubernetes, you need to define a StorageClass resource that specifies the provisioner and parameters for the storage backend. When a PVC requests storage from a StorageClass, Kubernetes dynamically provisions a PV based on the defined storage class.
Interviewer: What happens if a Persistent Volume Claim (PVC) cannot be satisfied in Kubernetes?
Candidate: If a PVC cannot be satisfied in Kubernetes, it remains in a pending state until a suitable Persistent Volume (PV) becomes available. If no suitable PV exists, the PVC remains unbound, and the associated Pod(s) may fail to start or operate correctly due to lack of storage.
Interviewer: How can you resize a Persistent Volume in Kubernetes?
Candidate: Persistent Volumes in Kubernetes do not support resizing once they are provisioned. However, you can manually resize the underlying storage volume outside of Kubernetes, then update the PVC to reflect the new size. Kubernetes will then re-bind the PVC to a suitable PV with the updated size.
Interviewer: What is the purpose of a Persistent Volume Claim (PVC) in Kubernetes?
Candidate: The purpose of a Persistent Volume Claim (PVC) in Kubernetes is to provide a way for Pods to request storage resources without needing to know the details of the underlying storage implementation. PVCs abstract away the storage provisioning details, allowing Pods to be more portable and decoupled from the specifics of the storage backend.
Interviewer: How do you delete a Persistent Volume in Kubernetes?
Candidate: To delete a Persistent Volume in Kubernetes, you first need to make sure that no PVCs are using the volume. Once all PVCs are deleted or updated to use different volumes, you can simply delete the PV resource using
kubectl delete pv [pv-name].{codeBox}Interviewer: Can you explain how storage classes are used in Kubernetes?
Candidate: Storage classes in Kubernetes provide a way to define different storage configurations and provisioners. They allow administrators to specify the type of storage to use and the parameters for provisioning, such as volume size, access mode, and reclaim policy. PVCs reference storage classes when requesting storage, allowing Kubernetes to dynamically provision the appropriate PV based on the defined class.
Read Back Day 5
Read Next Day 7{alertSuccess}