5.4 KiB

Raw Blame History

Storage Class Parameters

Some drivers support different settings for volumes. These can be configured via the driver configuration and/or storage classes.

`synology-iscsi`

The synology-iscsi driver supports several storage class parameters. Note however that not all parameters/values are supported for all backing file systems and LUN type. The following options are available:

Configure Storage Classes

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: synology-iscsi
parameters:
    fsType: ext4
    # The following options affect the LUN representing the volume. These options are passed directly to the Synology API.
    # The following options are known.
    lunTemplate: |
      type: BLUN       # Btrfs thin provisioning
      type: BLUN_THICK # Btrfs thick provisioning
      type: THIN       # Ext4 thin provisioning
      type: ADV        # Ext4 thin provisioning with legacy advanced feature set
      type: FILE       # Ext4 thick provisioning
      description: Some Description
      
      # Only for thick provisioned volumes. Known values:
      # 0: Buffered Writes
      # 3: Direct Write
      direct_io_pattern: 0
      
      # Device Attributes. See below for more info
      dev_attribs:
      - dev_attrib: emulate_tpws
        enable: 1
      - ...      

    # The following options affect the iSCSI target. These options will be passed directly to the Synology API.
    # The following options are known.
    targetTemplate: |
      has_header_checksum: false
      has_data_checksum: false
      
      # Note that this option requires a compatible filesystem. Use 0 for unlimited sessions.
      max_sessions: 0
      multi_sessions: true
      max_recv_seg_bytes: 262144
      max_send_seg_bytes: 262144

      # Use this to disable authentication. To configure authentication see below
      auth_type: 0

About LUN Types

The availability of the different types of LUNs depends on the filesystem used on your Synology volume. For Btrfs volumes you can use BLUN and BLUN_THICK volumes. For Ext4 volumes you can use THIN, ADV or FILE volumes. These correspond to the options available in the UI.

About `dev_attribs`

Most of the LUN options are configured via the dev_attribs list. This list can be specified both in the lunTemplate of the global configuration and in the lunTemplate of the StorageClass. If both lists are present they will be merged (with the StorageClass taking precedence). The following dev_attribs are known to work:

emulate_tpws: Hardware-assisted zeroing
emulate_caw: Hardware-assisted locking
emulate_3pc: Hardware-assisted data transfer
emulate_tpu: Space Reclamation
emulate_fua_write: Enable the FUA iSCSI command (DSM 7+)
emulate_sync_cache: Enable the Sync Cache iSCSI command (DSM 7+)
can_snapshot: Enable snapshots for this volume. Only works for thin provisioned volumes.

Configure Snapshot Classes

synology-iscsi can also configure different parameters on snapshot classes:

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotClass
metadata:
  name: synology-iscsi-snapshot
parameters:
  # This inline yaml object will be passed to the Synology API when creating the snapshot.
  lunSnapshotTemplate: |
    is_locked: true
    
    # https://kb.synology.com/en-me/DSM/tutorial/What_is_file_system_consistent_snapshot
    # Note that app consistent snapshots require a working Synology Storage Console. Otherwise both values will have
    # equivalent behavior.
    is_app_consistent: true    
...

Note that it is currently not supported by Synology devices to restore a snapshot onto a different volume. You can create volumes from snapshots, but you should use the same StorageClass as the original volume of the snapshot did.

Enabling CHAP Authentication

You can enable CHAP Authentication for StorageClasses by supplying an appropriate StorageClass secret (see the documentation for more details). You can use the same password for alle volumes of a StorageClass or use different passwords per volume.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: synology-iscsi-chap
parameters:
  fsType: ext4
  lunTemplate: |
    type: BLUN
    description: iSCSI volumes with CHAP Authentication    
secrets:
  # Use this to configure a single set of credentials for all volumes of this StorageClass
  csi.storage.k8s.io/provisioner-secret-name: chap-secret
  csi.storage.k8s.io/provisioner-secret-namespace: default
  # Use substitutions to use different credentials for volumes based on the PVC
  csi.storage.k8s.io/provisioner-secret-name: "${pvc.name}-chap-secret"
  csi.storage.k8s.io/provisioner-secret-namespace: "${pvc.namespace}"
...
---
# Use a secret like this to supply CHAP credentials.
apiVersion: v1
kind: Secret
metadata:
  name: chap-secret
stringData:
  # Client Credentials
  user: client
  password: MySecretPassword
  # Mutual CHAP Credentials. If these are specified mutual CHAP will be enabled.
  mutualUser: server
  mutualPassword: MyOtherPassword

Note that CHAP authentication will only be enabled if the secret contains a username and password. If e.g. a password is missing CHAP authentication will not be enabled (but the volume will still be created). You cannot automatically enable/disable CHAP or change the password after the volume has been created.

If the secret itself is referenced but not present, the volume will not be created.

5.4 KiB Raw Blame History