Creating a storage class

Create a storage class.

Required user type or access level: Cluster administrator

When you create a storage class, consider these storage classes and their associated quality of service (QoS).

Creating storage classes during IBM Cloud Private installation

You can create a storage class during the installation of IBM Cloud Private. After the installation is complete, the storage class is created and can be used for dynamic storage provisioning.

Note: Only Kubernetes storage classes are supported.

Complete these steps to provide a storage class definition file:

1. Create a YAML file with the storage class definitions. For information about storage class definitions, refer to the Kubernetes documentation.
2. Save the YAML file in the /<installation_directory>/cluster/misc/storage_class folder.

Note: Do not place any other files in the /misc/storage_class location. The IBM Cloud Private installer picks only the storage class YAML files from the directory and ignores any other file.

Storage class examples

For instructions to create GlusterFS and vSphere storage classes in IBM® Cloud Private, see Creating a storage class for GlusterFS and Creating a storage class for vSphere volume.

For a list of several storage class definitions, see Storage Classes .

Basic storage class

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name:  
provisioner: kubernetes.io/<plug-in-type>
parameters:
  parameter 1: value
  ...
  parameter N: value

Where:

• kind: StorageClass is the API.
• apiVersion: storage.k8s.io/v1 is the API version.
• metadata: name: is the name of the storage class.
• provisioner: kubernetes.io/<plug-in-type> is the name of the storage provisioner.
• parameters describe the volumes that belong to the storage class. Parameters are optional and they vary with the provisioner.

GlusterFS

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: slow
provisioner: kubernetes.io/glusterfs
parameters:
  resturl: "http://127.0.0.1:8081"
  clusterid: "630372ccdc720a92c681fb928f27b53f"
  restauthenabled: "true"
  restuser: "admin"
  secretNamespace: "default"
  secretName: "heketi-secret"
  gidMin: "40000"
  gidMax: "50000"
  volumetype: "replicate:3"

Where:

• resturl is a mandatory Gluster REST service URL or Heketi service URL that provisions Gluster volumes on demand. The general format is IP address:Port. If the Heketi service is exposed as a routable service in the Kubernetes configuration, the resturl can have a format like http://heketi-storage-project.cloudapps.mystorage.com, where the FQDN is a resolvable Heketi service URL.
• restauthenabled is a Gluster REST service authentication Boolean that enables authentication to the REST server. If this value is true, you must specify either restuser and restuserkey or secretNamespace + secretName. This option is deprecated; authentication is enabled when any of these parameters are specified:
  • restuser
  • restuserkey
  • secretName
  • secretNamespace
• restuser is the Gluster REST service user or Heketi user who can create volumes in the Gluster Trusted Pool.
• restuserkey is the password of the Gluster REST service user or Heketi user to use for authentication to the REST server. This option is deprecated in favor of secretNamespace + secretName.
• secretNamespace and secretName are optional. They identify a secret instance that contains the password to use to communicate with the Gluster REST service. If secretNamespace and secretName are not specified, an empty password is used. The provided secret must have type “kubernetes.io/glusterfs”.
• clusterid: 630372ccdc720a92c681fb928f27b53f is optional. This ID is the ID of the cluster that Heketi uses to provision the volume. It can also be a list of cluster IDs separated by commas.
• gidMin and gidMax are optional. They are the minimum and maximum values of the GID range for the storage class. A unique value (GID) in this range (gidMin - gidMax) is used for dynamically provisioned volumes. If gidMin and gidMax are not specified, the volume is provisioned with a value that is in the range 2000 - 2147483647, which are defaults for gidMin and gidMax, respectively.
• volumetype is the volume type and its parameters. The volume type is optional; if it isn't specified, the provisioner decides the volume type. Examples: ‘Replica volume’: volumetype: replicate:3 where 3 is the replica count; ‘Disperse/EC volume’: volumetype: disperse:4:2 where 4 is the data and 2 is the redundancy count; ‘Distribute volume’: volumetype: none.

vSphere

• Create a PersistentVolume with a user-specified disk format.

  kind: StorageClass
  apiVersion: storage.k8s.io/v1
  metadata:
   name: fast
  provisioner: kubernetes.io/vsphere-volume
  parameters:
   diskformat: zeroedthick
  

  Where the diskformat value is thin, zeroedthick, or eagerzeroedthick. The default value is thin.

• Create a PersistentVolume with a disk format on a user-specified datastore.

  kind: StorageClass
  apiVersion: storage.k8s.io/v1beta1
  metadata:
   name: fast
  provisioner: kubernetes.io/vsphere-volume
  parameters:
   diskformat: zeroedthick
   datastore: VSANDatastore
  

  • diskformat: thin, zeroedthick, or eagerzeroedthick. Default: thin.
    • datastore: You can also specify the datastore in the StorageClass. The volume is created on the datastore that is specified in the storage class, which in this case is VSANDatastore. This field is optional. If it isn't specified, as in the previous YAML description, the volume is created on the datastore that is specified in the vSphere config file that is used to initialize vSphere Cloud Provider.

• Create a PersistentVolume with user-specified VSAN storage capabilities.

  kind: StorageClass
  apiVersion: storage.k8s.io/v1beta1
  metadata:
    name: vsan-policy-fast
  provisioner: kubernetes.io/vsphere-volume
  parameters:
    diskformat: thin
    hostFailuresToTolerate: "1"
    diskStripes: "2"
    cacheReservation: "20"
    datastore: VSANDatastore
  

  You can specify VSAN storage capabilities for dynamic volume provisioning inside Kubernetes.

  Storage policies capture storage requirements, such as performance and availability, for PersistentVolumes. These policies determine how the container volume storage objects are provisioned and allocated within the datastore to ensure the requested quality of service. Storage policies are composed of storage capabilities, which are typically represented by a key-value pair. The key is a specific property that the datastore can offer. The value is a metric or a range that the datastore ensures for a provisioned object, such as a container volume that is backed by a virtual disk.

  VSAN exposes multiple storage capabilities. This table lists the VSAN storage capabilities that vSphere Cloud Provider supports:

While the vSphere infrastructure administrator creates a storage class inside Kubernetes, he or she can specify storage requirements for applications in terms of storage capabilities. When the administrator creates a StorageClass, he or she must specify the storage capability names that are used in table 1 because those names might differ from the ones that VSAN uses. For example, Number of disk stripes per object is referred to as stripeWidth in VSAN documentation. However, vSphere Cloud Provider uses the name diskStripes.

• Creating a storage class for GlusterFS
  
• Creating a storage class for vSphere volume