💾 Storage

A container's disk is temporary: when the pod is recreated, everything that was on it is lost. To store data that must survive (databases, uploads, files), Kubernetes uses persistent disks.

Term	What it is	Analogy
StorageClass	The type of disk available (for example, SSD)	The disk catalog
PVC (PersistentVolumeClaim)	The request for a disk, with a size	The purchase order
PV (PersistentVolume)	The disk itself, created automatically from the request	The delivered disk

In practice, you only create the PVC. The cluster creates the disk on its own.

info

The PVC is created with kubectl. The created disk can also be viewed in the Nuvion Panel (step 6).

---

🚀 Before you start

• Have cluster access configured (see Cluster Access).

🚀 1. See the available disk types

kubectl get storageclass

Note the name of the class marked (default). It is used when you do not choose one.

🚀 2. Request a disk (create the PVC)

Create the file pvc-dados.yaml:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-dados
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

kubectl apply -f pvc-dados.yaml

tip

If the list from step 1 has no (default) class, add the line storageClassName: CLASS-NAME inside spec.

ReadWriteOnce means the disk can be used by one node at a time.

🚀 3. Check the request

kubectl get pvc pvc-dados

The STATUS should be Bound (disk delivered). In some clusters the status stays Pending until a pod uses the disk, and that is normal. Go to step 4.

🚀 4. Use the disk in a pod

Create the file pod-storage.yaml. Each time the pod starts, it writes the date and time to the file /dados/historico.txt:

apiVersion: v1
kind: Pod
metadata:
  name: pod-storage
spec:
  containers:
    - name: app
      image: busybox
      command: ["sh", "-c", "date >> /dados/historico.txt; sleep 3600"]
      volumeMounts:
        - name: dados
          mountPath: /dados
  volumes:
    - name: dados
      persistentVolumeClaim:
        claimName: pvc-dados

kubectl apply -f pod-storage.yaml
kubectl get pvc pvc-dados
kubectl exec pod-storage -- cat /dados/historico.txt

The PVC becomes Bound and the file shows one line with the date.

🚀 5. Prove that the data survives

Delete the pod and create it again:

kubectl delete pod pod-storage
kubectl apply -f pod-storage.yaml
kubectl exec pod-storage -- cat /dados/historico.txt

Now the file shows two lines: the previous one and the new one. The pod was recreated, but the disk kept the data.

🚀 6. See the created disk

🖥️ Nuvion Panel

Go to Compute > Volumes and look for a new 1 GiB volume, created automatically by the cluster.

⌨️ kubectl (CLI)

kubectl get pv

The CLAIM column shows default/pvc-dados.

✅ How to know it worked

The file /dados/historico.txt accumulates a new line each time the pod is recreated.

warning

When you delete the PVC, the disk and all data are erased (in the default configuration). Deleting only the pod erases nothing.

❗ Common problems

Symptom	Cause	Solution
PVC Pending and the pod too	No default StorageClass	Add storageClassName to the PVC (step 2)
Pod stuck in ContainerCreating	The disk is still being prepared	Wait and see the Events section in kubectl describe pod pod-storage
Multi-Attach error	ReadWriteOnce disk in use by a pod on another node	Use only one pod with this disk, or make sure they stay on the same node
Requested size larger than allowed	Volume limit or quota	Request a smaller size or contact support

🧹 Cleanup

kubectl delete pod pod-storage
kubectl delete pvc pvc-dados

The second command erases the disk and the data.

➡️ Next step: Networking

🧠 Questions?

Talk to our SaveinCloud technical support team!