Encrypting PVCs using StorageClass with Kubernetes Secrets

Portworx Encrypted Volumes

Portworx has two different kinds of encrypted volumes:

• Encrypted Volumes

  Encrypted volumes are regular volumes which can be accessed from only one node.

• Encrypted Sharedv4 Volumes

  Encrypted sharedv4 volume allows access to the same encrypted volume from multiple nodes.

Using a StorageClass parameter, you can tell Portworx to encrypt all PVCs created using that StorageClass. Portworx uses a cluster wide secret to encrypt all the volumes created using the secure StorageClass.

Step 1: Create cluster wide secret key

A cluster wide secret key is a common key that points to a secret value/passphrase which can be used to encrypt all your volumes.

Create a cluster wide secret in Kubernetes, if not already created:

kubectl -n portworx create secret generic <your-secret-name> \
  --from-literal=cluster-wide-secret-key=<value>

Note that the cluster wide secret has to reside in the <your-secret-name> secret under the portworx namespace.

Now you have to give Portworx the cluster wide secret key, that acts as the default encryption key for all volumes.

PX_POD=$(kubectl get pods -l name=portworx -n kube-system -o jsonpath='{.items[0].metadata.name}')
kubectl exec $PX_POD -n kube-system -- /opt/pwx/bin/pxctl secrets set-cluster-key \
  --secret cluster-wide-secret-key

Step 2: Create a StorageClass

Create a storage class with the secure parameter set to true.

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: px-secure-sc
provisioner: kubernetes.io/portworx-volume
parameters:
  secure: "true"
  repl: "3"

To create a sharedv4 encrypted volume set the sharedv4 parameter to true as well.

Step 3: Create Persistent Volume Claim

Create a PVC that uses the above px-secure-sc storage class.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: secure-pvc
spec:
  storageClassName: px-secure-sc
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi

Step 4: Verify the volume

Once the PVC has been created, verify the volume created in Portworx is encrypted:

PX_POD=$(kubectl get pods -l name=portworx -n kube-system -o jsonpath='{.items[0].metadata.name}')
kubectl exec $PX_POD -n kube-system -- /opt/pwx/bin/pxctl volume list

ID                 NAME                                      ...  ENCRYPTED  ...
10852605918962284  pvc-5a885584-44ca-11e8-a17b-080027ee1df7  ...  yes        ...