Encrypt PVCs in GKE using annotations 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.
Encryption at Storage Class level does not allow using different secret keys for different PVCs. It also does not provide a way to disable encryption for certain PVCs that are using the same secure storage class. Encryption at PVC level will override the encryption options from Storage Class.
PVC level encryption is achieved using following PVC annotations:
px/secure
- Boolean which tells to secure the PVC or notpx/secret-name
- Name of the secret used to encryptpx/secret-namespace
- Namespace of the secret (Kubernetes Secrets only)px/secret-key
- Key to be used in the secret (Kubernetes Secrets only)
Encryption using cluster wide secret
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 px-vol-encryption \
--from-literal=cluster-wide-secret-key=<value>
Note that the cluster wide secret has to reside in the px-vol-encryption
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 <px-namespace> -o jsonpath='{.items[0].metadata.name}')
kubectl exec $PX_POD -n <px-namespace> -- /opt/pwx/bin/pxctl secrets set-cluster-key \
--secret cluster-wide-secret-key
Step 2: Create the secure PVC
If your Storage Class does not have the secure
flag set, but you want to encrypt the PVC using the same Storage Class, then create the PVC as below:
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: secure-pvc
annotations:
px/secure: "true"
spec:
storageClassName: portworx-sc
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 2Gi
As there is no px/secret-name
annotation specified, Portworx will default to the cluster wide secret to encrypt this PVC. If the cluster wide secret is not set, the volume creation will fail until the key is set.
Similar to the above example, if you want to use a Storage Class with secure
parameter set, but do not want to encrypt a certain PVC, then set the px/secure
annotation to false
.
If you are running Kubernetes version older than 1.9.4 (or < 1.8.9 in Kubernetes 1.8), then the PVC name has to be in ns.<namespace_of_pvc>-name.<identifier_for_pvc>
format to use the PVC-level encryption feature.
Encryption using custom secret key
Kubernetes secrets
You can encrypt your PVC using a custom secret as follows:
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: secure-mysql-pvc
annotations:
px/secret-name: volume-secrets
px/secret-namespace: portworx
px/secret-key: mysql-pvc
spec:
storageClassName: portworx-sc
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 2Gi
The encrypted PVC will use the key mysql-pvc
under the Kubernetes secret volume-secrets
in portworx
namespace. If the secret key is not present, then the volume creation will fail until the key is created.
From the annotations in the above PVC, only px/secret-name
is mandatory.
- If you do not specify the
px/secret-namespace
, Portworx will look for the secret in the PVC's namespace. - If you do not specify the
px/secret-key
, Portworx will look for a key with the PVC name.
By default, Portworx has get
and list
permissions for Kubernetes secrets from all the namespaces. In the above example, you can replace the px/secret-namespace
annotation with a namespace of your choice where you have created the Kubernetes secret.