The admin must define `StorageClass` objects that describe named "classes" of storage offered in a cluster. Different classes might map to arbitrary levels or policies determined by the admin. When configuring a `StorageClass` object for persistent volume provisioning, the admin will need to describe the type of provisioner to use and the parameters that will be used by the provisioner when it provisions a `PersistentVolume` belonging to the class.
The name of a StorageClass object is significant, and is how users can request a particular class, by specifying the name in their `PersistentVolumeClaim`. The `provisioner` field must be specified as it determines what volume plugin is used for provisioning PVs. The `parameters` field contains the parameters that describe volumes belonging to the storage class. Different parameters may be accepted depending on the `provisioner`. For example, the value `io1`, for the parameter `type`, and the parameter `iopsPerGB` are specific to EBS . When a parameter is omitted, some default is used.
See [Kubernetes StorageClass documentation](https://kubernetes.io/docs/user-guide/persistent-volumes/#storageclasses) for complete reference of all supported parameters.
*`iopsPerGB`: only for `io1` volumes. I/O operations per second per GiB. AWS volume plugin multiplies this with size of requested volume to compute IOPS of the volume and caps it at 20 000 IOPS (maximum supported by AWS, see AWS docs).
*`encrypted`: denotes whether the EBS volume should be encrypted or not. Valid values are `true` or `false`.
*`kmsKeyId`: optional. The full Amazon Resource Name of the key to use when encrypting the volume. If none is supplied but `encrypted` is true, a key is generated by AWS. See AWS docs for valid ARN value.
*`resturl` : Gluster REST service/Heketi service url which provision gluster volumes on demand. The general format should be `IPaddress:Port` and this is a mandatory parameter for GlusterFS dynamic provisioner. If Heketi service is exposed as a routable service in openshift/kubernetes setup, this can have a format similar to
`http://heketi-storage-project.cloudapps.mystorage.com` where the fqdn is a resolvable heketi service url.
*`restauthenabled` : Gluster REST service authentication boolean that enables authentication to the REST server. If this value is 'true', `restuser` and `restuserkey` or `secretNamespace` + `secretName` have to be filled. This option is deprecated, authentication is enabled when any of `restuser`, `restuserkey`, `secretName` or `secretNamespace` is specified.
*`restuserkey` : Gluster REST service/Heketi user's password which will be used for authentication to the REST server. This parameter is deprecated in favor of `secretNamespace` + `secretName`.
*`secretNamespace` + `secretName` : Identification of Secret instance that containes user password to use when talking to Gluster REST service. These parameters are optional, empty password will be used when both `secretNamespace` and `secretName` are omitted. The provided secret must have type "kubernetes.io/glusterfs".
*`clusterid`: `630372ccdc720a92c681fb928f27b53f` is the ID of the cluster which will be used by Heketi when provisioning the volume. It can also be a list of clusterids, for ex:
"8452344e2becec931ece4e33c4674e4e,42982310de6c63381718ccfa6d8cf397". This is an optional parameter.
*`gidMin` + `gidMax` : The minimum and maximum value of GID range for the storage class. A unique value (GID) in this range ( gidMin-gidMax ) will be used for dynamically provisioned volumes. These are optional values. If not specified, the volume will be provisioned with a value between 2000-2147483647 which are defaults for gidMin and gidMax respectively.
*`volumetype` : The volume type and it's parameters can be configured with this optional value. If the volume type is not mentioned, it's up to the provisioner to decide the volume type.
For example:
'Replica volume':
`volumetype: replicate:3` where '3' is replica count.
'Disperse/EC volume':
`volumetype: disperse:4:2` where '4' is data and '2' is the redundancy count.
'Distribute volume':
`volumetype: none`
For available volume types and it's administration options refer: ([Administration Guide](https://access.redhat.com/documentation/en-US/Red_Hat_Storage/3.1/html/Administration_Guide/part-Overview.html))
When the persistent volumes are dynamically provisioned, the Gluster plugin automatically create an endpoint and a headless service in the name `gluster-dynamic-<claimname>`. This dynamic endpoint and service will be deleted automatically when the persistent volume claim is deleted.
* **registry** Quobyte registry to use to mount the volume. You can specifiy the registry as <host>:<port> pair or if you want to specify multiple registries you just have to put a comma between them e.q. <host1>:<port>,<host2>:<port>,<host3>:<port>. The host can be an IP address or if you have a working DNS you can also provide the DNS names.
* **adminSecretName** secret that holds information about the Quobyte user and the password to authenticate agains the API server. The provided secret must have type "kubernetes.io/quobyte".
* **adminSecretNamespace** The namespace for **adminSecretName**. Default is `default`.
* **user** maps all access to this user. Default is `root`.
* **group** maps all access to this group. Default is `nfsnobody`.
* **quobyteConfig** use the specified configuration to create the volume. You can create a new configuration or modify an existing one with the Web console or the quobyte CLI. Default is `BASE`
* **quobyteTenant** use the specified tenant ID to create/delete the volume. This Quobyte tenant has to be already present in Quobyte. Default is `DEFAULT`
*`storageAccount`: Azure storage account name. If storage account is not provided, all storage accounts associated with the resource group are searched to find one that matches `skuName` and `location`. If storage account is provided, it must reside in the same resource group as the cluster, and `skuName` and `location` are ignored.
First we note there are no Persistent Volumes in the cluster. After creating a storage class and a claim including that storage class, we see a new PV is created
This section will guide you on how to configure and use the Ceph RBD provisioner.
##### Pre-requisites
For this to work you must have a functional Ceph cluster, and the `rbd` command line utility must be installed on any host/container that `kube-controller-manager` or `kubelet` is running on.
##### Configuration
First we must identify the Ceph client admin key. This is usually found in `/etc/ceph/ceph.client.admin.keyring` on your Ceph cluster nodes. The file will look something like this:
From the key value, we will create a secret. We must create the Ceph admin Secret in the namespace defined in our `StorageClass`. In this example we've set the namespace to `kube-system`.
Now modify `examples/persistent-volume-provisioning/rbd/rbd-storage-class.yaml` to reflect your environment, particularly the `monitors` field. We are now ready to create our RBD Storage Class:
The kube-controller-manager is now able to provision storage, however we still need to be able to map the RBD volume to a node. Mapping should be done with a non-privileged key, if you have existing users you can get all keys by running `ceph auth list` on your Ceph cluster with the admin key. For this example we will create a new user and pool.
This key will be made into a secret, just like the admin secret. However this user secret will need to be created in every namespace where you intend to consume RBD volumes provisioned in our example storage class. Let's create a namespace called `myns`, and create the user secret in that namespace.
$ export PODNAME=`kubectl get pod --selector='role=server' --namespace=myns --output=template --template="{{with index .items 0}}{{.metadata.name}}{{end}}"`
