Add documentation about default storage class

_data/tasks.yml

@@ -65,6 +65,7 @@ toc:
   - docs/tasks/administer-cluster/safely-drain-node.md
   - docs/tasks/administer-cluster/change-pv-reclaim-policy.md
   - docs/tasks/administer-cluster/limit-storage-consumption.md
+  - docs/tasks/administer-cluster/change-default-storage-class.md
   - docs/tasks/administer-cluster/share-configuration.md
 
 - title: Administering Federation

docs/tasks/administer-cluster/change-default-storage-class.md

@@ -0,0 +1,90 @@
+---
+title: Changing the default StorageClass
+---
+
+{% capture overview %}
+This page shows how to change the default Storage Class that is used to
+provision volumes for PersistentVolumeClaims that have no special requirements.
+
+{% endcapture %}
+
+{% capture prerequisites %}
+
+{% include task-tutorial-prereqs.md %}
+
+{% endcapture %}
+
+{% capture steps %}
+
+## Why change the default storage class?
+
+Depending on the installation method, your Kubernetes cluster may be deployed with
+an existing StorageClass that is marked as default. This default StorageClass
+is then used to dynamically provision storage for PersistentVolumeClaims
+that do not require any specific storage class. See
+[PersistentVolumeClaim documentation](/docs/user-guide/persistent-volumes/#class-1)
+for details.
+
+The pre-installed default StorageClass may not fit well with your expected workload;
+for example, it might provision storage that is too expensive. If this is the case,
+you can either change the default StorageClass or disable it completely to avoid
+dynamic provisioning of storage.
+
+Simply deleting the default StorageClass may not work, as it may be re-created
+automatically by the addon manager running in your cluster. Please consult the docs for your installation
+for details about addon manager and how to disable individual addons.
+
+## Changing the default StorageClass
+
+1. List the StorageClasses in your cluster:
+
+        kubectl get storageclass
+
+    The output is similar to this:
+
+        NAME                 TYPE
+        standard (default)   kubernetes.io/gce-pd
+        gold                 kubernetes.io/gce-pd
+
+   The default StorageClass is marked by `(default)`.
+
+1. Mark the default StorageClass as non-default:
+
+   The default StorageClass has an annotation
+   `storageclass.kubernetes.io/is-default-class` set to `true`. Any other value
+   or absence of the annotation is interpreted as `false`.
+
+   To mark a StorageClass as non-default, you need to change its value to `false`:
+
+        kubectl patch storageclass <your-class-name> -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}'
+
+    where `<your-class-name>` is the name of your chosen StorageClass.
+
+1. Mark a StorageClass as default:
+
+   Similarly to the previous step, you need to add/set the annotation
+   `storageclass.kubernetes.io/is-default-class=true`.
+
+        kubectl patch storageclass <your-class-name> -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}'
+
+   Please note that at most one StorageClass can be marked as default. If two
+   or more of them are marked as default, Kubernetes ignores the annotation,
+   i.e. it behaves as if there is no default StorageClass.
+
+1. Verify that your chosen StorageClass is default:
+
+        kubectl get storageclass
+
+    The output is similar to this:
+
+        NAME             TYPE
+        standard         kubernetes.io/gce-pd
+        gold (default)   kubernetes.io/gce-pd
+
+{% endcapture %}
+
+{% capture whatsnext %}
+* Learn more about [StorageClasses](/docs/user-guide/persistent-volumes/).
+{% endcapture %}
+
+{% include templates/task.md %}

docs/tasks/index.md

@@ -54,6 +54,7 @@ single thing, typically by giving a short sequence of steps.
 * [Autoscaling the DNS Service in a Cluster](/docs/tasks/administer-cluster/dns-horizontal-autoscaling/)
 * [Safely Draining a Node while Respecting Application SLOs](/docs/tasks/administer-cluster/safely-drain-node/)
 * [Changing reclaim policy of a PersistentVolume](/docs/tasks/administer-cluster/change-pv-reclaim-policy/)
+* [Changing the default StorageClass](/docs/tasks/administer-cluster/change-default-storage-class/)
 
 #### Managing Stateful Applications
 

docs/user-guide/persistent-volumes/index.md

@@ -329,7 +329,7 @@ is turned on.
 * If the admission plugin is turned on, the administrator may specify a
 default `StorageClass`. All PVCs that have no `storageClassName` can be bound only to
 PVs of that default. Specifying a default `StorageClass` is done by setting the
-annotation `storageclass.beta.kubernetes.io/is-default-class` equal to "true" in
+annotation `storageclass.kubernetes.io/is-default-class` equal to "true" in
 a `StorageClass` object. If the administrator does not specify a default, the
 cluster responds to PVC creation as if the admission plugin were turned off. If
 more than one default is specified, the admission plugin forbids the creation of
@@ -339,6 +339,9 @@ all PVCs.
 have no class. In this case, the PVCs that have no `storageClassName` are treated the
 same way as PVCs that have their `storageClassName` set to `""`.
 
+Depending on installation method, a default StorageClass may be deployed
+to Kubernetes cluster by addon manager during installation.
+
 When a PVC specifies a `selector` in addition to requesting a `StorageClass`,
 the requirements are ANDed together: only a PV of the requested class and with
 the requested labels may be bound to the PVC. Note that currently, a PVC with a