Clean up configure-persistent-volume-storage task (#16907)

2019-11-26 05:21:10 +00:00
parent 3fa00be466
commit 6551689040
1 changed files with 90 additions and 31 deletions
@@ -6,22 +6,26 @@ weight: 60

 {{% capture overview %}}

-This page shows how to configure a Pod to use a PersistentVolumeClaim for storage.
+This page shows yo how to configure a Pod to use a
+{{< glossary_tooltip text="PersistentVolumeClaim" term_id="persistent-volume-claim" >}}
+for storage.
 Here is a summary of the process:

-1. A cluster administrator creates a PersistentVolume that is backed by physical
-storage. The administrator does not associate the volume with any Pod.
+1. You, as cluster adminstrator, create a PersistentVolume backed by physical
+storage. You do not associate the volume with any Pod.

-1. A cluster user creates a PersistentVolumeClaim, which gets automatically
-bound to a suitable PersistentVolume.
+1. You, now taking the role of a developer / cluster user, create a
+PersistentVolumeClaim that is automatically bound to a suitable
+PersistentVolume.

-1. The user creates a Pod that uses the PersistentVolumeClaim as storage.
+1. You create a Pod that uses the above PersistentVolumeClaim for storage.

 {{% /capture %}}

 {{% capture prerequisites %}}

-* You need to have a Kubernetes cluster that has only one Node, and the kubectl
+* You need to have a Kubernetes cluster that has only one Node, and the
+{{< glossary_tooltip text="kubectl" term_id="kubectl" >}}
 command-line tool must be configured to communicate with your cluster. If you
 do not already have a single-node cluster, you can create one by using
 [Minikube](/docs/getting-started-guides/minikube).
@@ -35,17 +39,44 @@ do not already have a single-node cluster, you can create one by using

 ## Create an index.html file on your Node

-Open a shell to the Node in your cluster. How you open a shell depends on how
-you set up your cluster. For example, if you are using Minikube, you can open a
-shell to your Node by entering `minikube ssh`.
+Open a shell to the single Node in your cluster. How you open a shell depends
+on how you set up your cluster. For example, if you are using Minikube, you
+can open a shell to your Node by entering `minikube ssh`.

-In your shell, create a `/mnt/data` directory:
+In your shell on that Node, create a `/mnt/data` directory:
+
+```shell
+# This assumes that your Node uses "sudo" to run commands
+# as the superuser
+sudo mkdir /mnt/data
+```

-    sudo mkdir /mnt/data

 In the `/mnt/data` directory, create an `index.html` file:

-    sudo sh -c "echo 'Hello from Kubernetes storage' > /mnt/data/index.html"
+```shell
+# This again assumes that your Node uses "sudo" to run commands
+# as the superuser
+sudo sh -c "echo 'Hello from Kubernetes storage' > /mnt/data/index.html"
+```
+
+{{< note >}}
+If your Node uses a tool for superuser access other than `sudo`, you can
+usually make this work if you replace `sudo` with the name of the other tool.
+{{< /note >}}
+
+Test that the `index.html` file exists:
+
+```shell
+cat /mnt/data/index.html
+```
+
+The output should be:
+```
+Hello from Kubernetes storage
+```
+
+You can now close the shell to your Node.

 ## Create a PersistentVolume

@@ -73,11 +104,15 @@ PersistentVolumeClaim requests to this PersistentVolume.

 Create the PersistentVolume:

-    kubectl apply -f https://k8s.io/examples/pods/storage/pv-volume.yaml
+```shell
+kubectl apply -f https://k8s.io/examples/pods/storage/pv-volume.yaml
+```

 View information about the PersistentVolume:

-    kubectl get pv task-pv-volume
+```shell
+kubectl get pv task-pv-volume
+```

 The output shows that the PersistentVolume has a `STATUS` of `Available`. This
 means it has not yet been bound to a PersistentVolumeClaim.
@@ -107,7 +142,9 @@ claim to the volume.

 Look again at the PersistentVolume:

-    kubectl get pv task-pv-volume
+```shell
+kubectl get pv task-pv-volume
+```

 Now the output shows a `STATUS` of `Bound`.

@@ -116,7 +153,9 @@ Now the output shows a `STATUS` of `Bound`.

 Look at the PersistentVolumeClaim:

-    kubectl get pvc task-pv-claim
+```shell
+kubectl get pvc task-pv-claim
+```

 The output shows that the PersistentVolumeClaim is bound to your PersistentVolume,
 `task-pv-volume`.
@@ -138,28 +177,42 @@ is a volume.

 Create the Pod:

-    kubectl apply -f https://k8s.io/examples/pods/storage/pv-pod.yaml
+```shell
+kubectl apply -f https://k8s.io/examples/pods/storage/pv-pod.yaml
+```

-Verify that the Container in the Pod is running;
+Verify that the container in the Pod is running;

-    kubectl get pod task-pv-pod
+```shell
+kubectl get pod task-pv-pod
+```

-Get a shell to the Container running in your Pod:
+Get a shell to the container running in your Pod:

-    kubectl exec -it task-pv-pod -- /bin/bash
+```shell
+kubectl exec -it task-pv-pod -- /bin/bash
+```

 In your shell, verify that nginx is serving the `index.html` file from the
 hostPath volume:

-    root@task-pv-pod:/# apt-get update
-    root@task-pv-pod:/# apt-get install curl
-    root@task-pv-pod:/# curl localhost
+```shell
+# Be sure to run these 3 commands inside the root shell that comes from
+# running "kubectl exec" in the previous step
+apt update
+apt install curl
+curl http://localhost/
+```

 The output shows the text that you wrote to the `index.html` file on the
 hostPath volume:

    Hello from Kubernetes storage

+
+If you see that message, you have successfully configured a Pod to
+use storage from a PersistentVolumeClaim.
+
 ## Clean up

 Delete the Pod,  the PersistentVolumeClaim and the PersistentVolume:
@@ -170,14 +223,20 @@ kubectl delete pvc task-pv-claim
 kubectl delete pv task-pv-volume
 ```

-Open the shell to the Node in your cluster again (how you open a shell depends on how
-you set up your cluster. For example, if you are using Minikube, you can open a
-shell to your Node by entering `minikube ssh`) and remove the file:
+If you don't already have a shell open to the Node in your cluster,
+open a new shell the same way that you did earlier.
+
+In the shell on your Node, remove the file and directory that you created:

 ```shell
-sudo rm -rf /mnt/data
+# This assumes that your Node uses "sudo" to run commands
+# as the superuser
+sudo rm /mnt/data/index.html
+sudo rmdir /mnt/data
 ```

+You can now close the shell to your Node.
+
 {{% /capture %}}


@@ -201,10 +260,10 @@ metadata:
    pv.beta.kubernetes.io/gid: "1234"
 ```
 When a Pod consumes a PersistentVolume that has a GID annotation, the annotated GID
-is applied to all Containers in the Pod in the same way that GIDs specified in the
+is applied to all containers in the Pod in the same way that GIDs specified in the
 Pod’s security context are. Every GID, whether it originates from a PersistentVolume
 annotation or the Pod’s specification, is applied to the first process run in
-each Container.
+each container.

 {{< note >}}
 When a Pod consumes a PersistentVolume, the GIDs associated with the