In Kubernetes, Pods are ephemeral<\/strong>, meaning any data stored inside a Pod is lost if the Pod is deleted or restarted. This can create challenges for applications like databases, content management systems, or file storage<\/strong> that require persistent data<\/strong>.<\/p>\n\n\n\n Kubernetes addresses this with Persistent Volumes (PV)<\/strong> and Persistent Volume Claims (PVC)<\/strong>:<\/p>\n\n\n\n By using PVs and PVCs, you can ensure data persists beyond the lifecycle of a Pod<\/strong>, decouple storage from compute, and manage storage efficiently.<\/p>\n\n\n\n Before you start, ensure the following:<\/p>\n\n\n\n A PV is the actual storage resource in your cluster. Here\u2019s an example with a label selector<\/strong>:<\/p>\n\n\n\n Apply the PV:<\/strong><\/p>\n\n\n\n A PVC is a request for storage that binds to a matching PV:<\/p>\n\n\n\n Apply the PVC:<\/strong><\/p>\n\n\n\n Mount the PVC inside a Pod to give your container access to persistent storage:<\/p>\n\n\n\n Apply the Pod:<\/strong><\/p>\n\n\n\n Any data written to 1. Exec into the pod:<\/p>\n\n\n\n 2. Create a file in the mounted volume:<\/p>\n\n\n\n 3. Exit the Pod and delete it:<\/p>\n\n\n\n 4. Create a new Pod<\/strong> using the same PVC:<\/p>\n\n\n\n Apply the new Pod and check the file:<\/p>\n\n\n\n\n
Prerequisites<\/h2>\n\n\n\n
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Step 1: Create a Persistent Volume (PV)<\/h2>\n\n\n\n
apiVersion: v1\nkind: PersistentVolume\nmetadata:\n name: pv-demo\n labels:\n type: fast-storage\nspec:\n capacity:\n storage: 1Gi\n accessModes:\n - ReadWriteOnce\n hostPath:\n path: \"\/mnt\/data\"\n<\/code><\/pre>\n\n\n\nkubectl apply -f pv.yaml<\/code><\/pre>\n\n\n\nkubectl get pv<\/code><\/pre>\n\n\n\nStep 2: Create a Persistent Volume Claim (PVC)<\/h2>\n\n\n\n
apiVersion: v1\nkind: PersistentVolumeClaim\nmetadata:\n name: pvc-demo\nspec:\n accessModes:\n - ReadWriteOnce\n resources:\n requests:\n storage: 500Mi\n selector:\n matchLabels:\n type: fast-storage<\/code><\/pre>\n\n\n\nkubectl apply -f pvc.yaml<\/code><\/pre>\n\n\n\nkubectl get pvc<\/code><\/pre>\n\n\n\nStep 3: Use the PVC in a Pod<\/h2>\n\n\n\n
apiVersion: v1\nkind: Pod\nmetadata:\n name: pod-with-pvc\nspec:\n containers:\n - name: nginx\n image: nginx:latest\n volumeMounts:\n - mountPath: \"\/usr\/share\/nginx\/html\" # Path inside the Pod\n name: storage\n volumes:\n - name: storage\n persistentVolumeClaim:\n claimName: pvc-demo<\/code><\/pre>\n\n\n\nkubectl apply -f pod-with-pvc.yaml<\/code><\/pre>\n\n\n\nkubectl get pods<\/code><\/pre>\n\n\n\n\/usr\/share\/nginx\/html<\/code> In the Pod is actually stored in the PV (\/mnt\/data<\/code>on the worker node).<\/p>\n\n\n\nStep 4: Verify Data Persistence<\/h2>\n\n\n\n
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kubectl exec -it pod-with-pvc -- \/bin\/bash<\/strong><\/code><\/pre>\n\n\n\necho \"Hello Kubernetes\" > \/usr\/share\/nginx\/html\/index.html<\/strong><\/code><\/pre>\n\n\n\nkubectl delete pod pod-with-pvc<\/strong><\/code><\/pre>\n\n\n\napiVersion: v1\nkind: Pod\nmetadata:\n name: new-pod-with-pvc\nspec:\n containers:\n - name: nginx\n image: nginx:latest\n volumeMounts:\n - mountPath: \"\/usr\/share\/nginx\/html\"\n name: storage\n volumes:\n - name: storage\n persistentVolumeClaim:\n claimName: pvc-demo<\/code><\/pre>\n\n\n\nkubectl apply -f new-pod-with-pvc.yaml\nkubectl exec -it new-pod-with-pvc -- cat \/usr\/share\/nginx\/html\/index.html<\/code><\/pre>\n\n\n\n