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Dynamic Provisioning

Dynamic Provisioning is an automated mechanism in Kubernetes that creates Persistent Volumes (PV) on-demand, eliminating the need for administrators to manually pre-provision storage.^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md]

Mechanism

The core of Dynamic Provisioning relies on the StorageClass API object^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md]. A StorageClass functions as a template for creating PVs, defining two key components^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md]:

  1. PV Properties: Attributes such as storage type and volume size^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md].
  2. Storage Plugin: The provisioner (e.g., Ceph, NFS) responsible for creating the volume^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md].

Workflow

When a developer creates a PersistentVolumeClaim (PVC) that specifies a storageClassName, Kubernetes attempts to find a matching StorageClass^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md]. Once found, Kubernetes invokes the declared storage plugin to automatically provision a new PV that meets the PVC's requirements^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md].

The system binds the PVC to this new PV only if the storage specifications (e.g., capacity) and the storageClassName match^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md].

Benefits

This automation solves the scalability problem inherent in manual provisioning, where administrators would struggle to create thousands of PVs in advance^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md]. It ensures that storage is available "just-in-time" without disrupting existing users or requiring changes to PVC definitions^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md].

Sources

^[400-devops__06-Kubernetes__k8s-paas__原理及源码解析__Kubernetes_yaml文件.md]