Example: Mounting a PersistentVolume for Dynamic Provisioning

This example also uses a PersistentVolume. However, unlike the previous example, when you use the MapR dynamic provisioner, you do not need to create a PersistentVolume manually. The PersistentVolume is created automatically based on the parameters specified in the referenced StorageClass.

Dynamic provisioning is useful in cases where you do not want MapR and Kubernetes administrators to create storage manually to store the Pod storage state.

The following example uses a PersistentVolumeClaim that references a Storage Class. In this example, a Kubernetes Administrator has created a storage class called secure-maprfs for Pod creators to use when they want to create persistent storage for their Pods. In this example, it is important for the created Pod storage to survive the deletion of a Pod.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
   name: secure-maprfs
   namespace: mapr-examples
provisioner: mapr.com/maprfs
parameters:
    restServers: "rest1:8443"
    cldbHosts: "cldb1 cldb2 cldb3"
    cluster: "mysecurecluster"
    securityType: "secure"
    ticketSecretName: "mapr-ticket-secret"
    ticketSecretNamespace: "mapr-examples"
    maprSecretName: "mapr-provisioner-secrets"
    maprSecretNamespace: "mapr-examples"
    namePrefix: "pv"
    mountPrefix: "/pv"
    readOnly: "true"
    reclaimPolicy: "Retain"
    advisoryquota: "100M"
    readonly: "1"

---

kind: Pod
apiVersion: v1
metadata:
  name: test-secure-provisioner
  namespace: mapr-examples
spec:
  containers:
  - name: busybox
    image: busybox
    args:
    - sleep
    - "1000000"
    imagePullPolicy: Always
    volumeMounts:
      - name: maprfs-pvc
        mountPath: "/dynvolume"
  restartPolicy: "Never"
  volumes:
    - name: maprfs-pvc
      persistentVolumeClaim:
        claimName: maprfs-secure-pvc

---

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: maprfs-secure-pvc
  namespace: mapr-examples
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: secure-maprfs
  resources:
    requests:
      storage: 300M
---

apiVersion: v1
kind: Secret
metadata:
  name: mapr-provisioner-secrets
  namespace: mapr-examples
type: Opaque
data:
  MAPR_CLUSTER_USER: CHANGETHIS!
  MAPR_CLUSTER_PASSWORD: CHANGETHIS!

---

apiVersion: v1
kind: Secret
metadata:
  name: mapr-ticket-secret
  namespace: mapr-examples
type: Opaque
data:
  CONTAINER_TICKET: <BASE64 ENCODED VERSION OF CONTENTS OF TICKET FILE>

The following tables describe the parameters in the example:

StorageClass

Parameter Notes
apiVersion The Kubernetes APi version for the StorageClass spec.
kind The kind of object being created. This is a StorageClass.
metadata: name The name of the StorageClass. Administrators should specify the name carefully because it will be used by Pod authors to help select the right StorageClass for their needs.
metadata: namespace The namespace in which the StorageClass runs. This namespace can be different from the namespace used by the PVC and Pod, since the StorageClass namespace can be a cross-namespace resource.
provisioner The provisioner being used. for the MapR provisioner, specify mapr.com/maprfs.
restServers A space-separated list of MapR webservers. Specify the hostname or IP address and port number of each REST server for the MapR cluster. For fault tolerance, providing multiple REST server hosts is recommended.
cldbHosts The hostname or IP addresses of the CLDB hosts for the MapR cluster. You must provide at least one CLDB host. For fault-tolerance, providing multiple CLDB hosts is recommended. To specify multiple hosts, separate each name or IP address by a space.
cluster The MapR cluster name.
securityType A parameter that indicates whether MapR tickets are used or not used. If MapR tickets are used, specify secure. Otherwise, specify unsecure.
ticketSecretName The name of the Secret that contains the ticket to use when mounting to the MapR cluster. See Configuring a Secret.
ticketSecretNamespace The namespace that contains the Secret. Use the same namespace as the namespace used by the Pod.
maprSecretName The name of the Kubernetes Secret that is used to store MapR administrative credentials (user, password, and ticket information for the MapR webserver). To use the provisioner, you must configure a Secret. See Configuring a Secret.
maprSecretNamespace The namespace for the Secret containing the MapR administrative credentials (user name and password information for a MapR user that has the privileges to create MapR volumes). This namespace can be different from the namespace used by the Pod, since a Pod author or namespace admin might not be trusted to create administration Secrets for the MapR cluster.
namePrefix A prefix for the MapR volume to be created. For example, if you specify PV as the namePrefix, the first dynamically created volume might be named PV.bevefsescr. The provisioner generates random names using lower-case letters. If you do not specify a prefix, the provisioner uses maprprovisioner as a prefix.
mountPrefix The parent path of the mount in MapR file system. If you do not specify a mount prefix, the provisioner mounts your volume under the MapR root.
readOnly This parameter specifies that the POSIX driver should mount the MapR path as read only. This is different from the readonly parameter for volume creation that creates the volume as read only.
reclaimPolicy Kubernetes does not currently support passing a non-delete reclaim policy to the StorageClass. This parameter allows you to specify Retain. This ensures that provisioned volumes are not automatically deleted when their calling Pods are deleted. If you specify Retain, you must clean up your provisioned volumes manually.
advisoryquota The advisory storage quota for the MapR volume. advisoryquota is one of the MapR parameters that you can specify for dynamic provisioning. For more information, see Before You Begin.
readonly When the value is 1, this parameter specifies that the MapR volume should be created as read-only. This is different from the readOnly parameter that mounts the MapR path as read only.

Pod

Parameter Notes
apiVersion The Kubernetes API version for the Pod spec.
kind The kind of object being created. For clarity, this example uses a naked Pod. Generally, it is better to use a Deployment, DaemonSet, or StatefulSet for high availability and ease of upgrade.
metadata: name The Pod name.
metadata: namespace The namespace in which the Pod runs. It should be the same namespace in which the PVC runs.
volumeMounts: mountPath A directory inside the container that is designated as the mount path.
volumeMounts: name A name that you assign to the Kubernetes volumeMounts resource. The value should match Volumes: name.
Volumes: name A string to identify the name of the Kubernetes volumes resource. The value should match volumeMounts: name.
persistentVolumeClaim: claimName The name of the PersistentVolumeClaim (PVC). For more information, see PersistentVolumeClaims.

PVC

Parameter Notes
apiVersion The Kubernetes API version for the Pod spec.
kind The kind of object being created. This is a PersistentVolumeClaim (PVC).
metadata: name The PVC name.
metadata: namespace The namespace in which the PVC runs. This should be the same namespace used by the Pod.
accessModes How the PersistentVolume is mounted on the host. Only ReadWriteOnce (RWO) is supported. (This is a limitation of the FlexVolume driver.) For more information, see Access Modes.
storageClassName The name of the storage class requested by the PersistentVolumeClaim. For more information, see Dynamic Provisioning and Storage Classes.
requests: storage The storage resources being requested, or that were requested and have been allocated. The Pod author can use this parameter to tell MapR how much quota is needed for the MapR volume. For the units, see Resource Model.

Provisioner Secret

In the mapr-provisioner-secrets Secret:

Parameter Notes
MAPR_CLUSTER_USER This is the base64-encoded user ID used to log in to the MapR REST server and create or delete volumes. See Converting a String to Base64. For more information about Secrets, see Secrets.
MAPR_CLUSTER_PASSWORD This is the base64-encoded password for the MAPR_CLUSTER_USER. See Converting a String to Base64. For more information about Secrets, see Secrets.

Ticket Secret

In the mapr-ticket-secret Secret:

Parameter Notes
CONTAINER_TICKET The contents of the MapR ticket encoded in base64. If you specified secure for the securityType, you must provide the ticket. To encode the ticket, see Converting a String to Base64. You may remove the ticket if the MapR cluster is not secure. For more information about Secrets, see Secrets.