Volume Security

Available as of v1.4.0

Harvester v1.4.0 and later versions allow you to encrypt and decrypt virtual machine images. The encryption mechanism utilizes the Linux kernel module dm_crypt and the command-line utility cryptsetup.

Prerequisites

Prepare the following resources:

• Secret: A Kubernetes secret is used as the passphrase of dm_crypt. You must specify the value of the CRYPTO_KEY_VALUE field. All other fields are fixed.

  

  Example Secret:

  apiVersion: v1
  kind: Secret
  metadata:
    name: encryption
    namespace: default
  data:
    CRYPTO_KEY_CIPHER: aes-xts-plain64
    CRYPTO_KEY_HASH: sha256
    CRYPTO_KEY_PROVIDER: secret
    CRYPTO_KEY_SIZE: 256
    CRYPTO_KEY_VALUE: "Your encryption passphrase"
    CRYPTO_PBKDF: argon2i
  important

  You can create a secret in the system namespace using kubectl or the Harvester UI (Edit as YAML feature). Resources in the system namespace are not displayed on the Harvester UI Secrets screen.

• StorageClass: Images are encrypted using Longhorn, so required fields must be passed to the Longhorn CSI Driver. You can specify the encryption secret when creating a StorageClass. For more information, see Image StorageClass.

  

  Example of a StorageClass:

  allowVolumeExpansion: true
  apiVersion: storage.k8s.io/v1
  kind: StorageClass
  metadata:
    name: encryption
  parameters:
    csi.storage.k8s.io/node-publish-secret-name: encryption
    csi.storage.k8s.io/node-publish-secret-namespace: default
    csi.storage.k8s.io/node-stage-secret-name: encryption
    csi.storage.k8s.io/node-stage-secret-namespace: default
    csi.storage.k8s.io/provisioner-secret-name: encryption
    csi.storage.k8s.io/provisioner-secret-namespace: default
    encrypted: "true"
    migratable: "true"
    numberOfReplicas: "3"
    staleReplicaTimeout: "2880"
  provisioner: driver.longhorn.io
  reclaimPolicy: Delete
  volumeBindingMode: Immediate
  important

  The example contains the default YAML code for Kubernetes secrets. Aside from this, you can use encryption options for LUKS mode, which is a cryptsetup operating mode. Harvester v1.4.1 and later versions support these options, but you must verify that these are supported by your nodes.

  Option	Possible Values
  CRYPTO_KEY_CIPHER	aes-xts-plain, aes-xts-plain64, aes-cbc-plain, aes-cbc-plain64, aes-cbc-essiv:sha256
  CRYPTO_KEY_HASH	sha256, sha384, sha512
  CRYPTO_KEY_SIZE	256, 384, 512
  CRYPTO_PBKDF	argon2i, argon2id, pbkdf2

  You can create a secret in the system namespace using kubectl or the Harvester UI (Edit as YAML feature). Resources in the system namespace are not displayed on the Harvester UI Secrets screen.

Encrypted Volumes

You can create an encrypted volume using an encrypted StorageClass on the following UI locations:

• Volumes: Create screen

  

• Volumes tab on the Virtual Machine: Create screen

  

Advanced Usage with Rancher Integration

The secret is an unencrypted Base64-encoded string. To keep the secret safe, you can use projects and namespaces to isolate permissions. For more information, see Multi-Tenancy.

Limitations

You cannot perform the following actions:

• Export a new volume from an encrypted volume
• Restore an encrypted volume to an unencrypted volume
• Restore an unencrypted volume to an encrypted volume