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add pv protection description (#7620)

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Yuquan Ren
2018-03-05 17:39:51 +08:00
committed by zacharysarah
parent 9e96858424
commit f8a1cd6aa8
3 changed files with 18 additions and 225 deletions
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_data/tasks.yml
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@@ -186,9 +186,15 @@ toc:
- docs/tasks/administer-cluster/configure-multiple-schedulers.md
- docs/tasks/administer-cluster/ip-masq-agent.md
- docs/tasks/administer-cluster/dns-custom-nameservers.md
<<<<<<< HEAD
- docs/tasks/administer-cluster/dns-debugging-resolution.md
- docs/tasks/administer-cluster/pvc-protection.md
- docs/tasks/administer-cluster/storage-object-in-use-protection.md
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- docs/tasks/administer-cluster/pvc-protection.md
=======
- docs/tasks/administer-cluster/storage-object-in-use-protection.md
>>>>>>> add pv protection description (#7620)
- title: Federation - Run an App on Multiple Clusters
landing_page: /docs/tasks/federation/set-up-cluster-federation-kubefed/
docs/concepts/storage/persistent-volumes.md
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@@ -74,6 +74,7 @@ Once a user has a claim and that claim is bound, the bound PV belongs to the use
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### Storage Object in Use Protection
{% assign for_k8s_version="v1.10" %}{% include feature-state-beta.md %}
<<<<<<< HEAD
The purpose of the Storage Object in Use Protection feature is to ensure that Persistent Volume Claims (PVCs) in active use by a pod and Persistent Volume (PVs) that are bound to PVCs are not removed from the system as this may result in data loss.
||||||| merged common ancestors
### Persistent Volume Claim Protection
@@ -95,10 +96,16 @@ The purpose of the Storage Protection feature is to ensure that Persistent Volum
=======
The purpose of the Storage Object in Use Protection feature is to ensure that Persistent Volume Claims (PVCs) in active use by a pod are not removed from the system as this may result in data loss.
>>>>>>> Storage Protection was renamed to Storage Object in Use Protection (#7576)
||||||| merged common ancestors
The purpose of the Storage Object in Use Protection feature is to ensure that Persistent Volume Claims (PVCs) in active use by a pod are not removed from the system as this may result in data loss.
=======
The purpose of the Storage Object in Use Protection feature is to ensure that Persistent Volume Claims (PVCs) in active use by a pod and Persistent Volume (PVs) that are bound to PVCs are not removed from the system as this may result in data loss.
>>>>>>> add pv protection description (#7620)
**Note:** PVC is in active use by a pod when the pod status is `Pending` and the pod is assigned to a node or the pod status is `Running`.
{: .note}
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When the [Storage Object in Use Protection beta feature](/docs/tasks/administer-cluster/storage-object-in-use-protection/) is enabled, if a user deletes a PVC in active use by a pod, the PVC is not removed immediately. PVC removal is postponed until the PVC is no longer actively used by any pods, and also if admin deletes a PV that is bound to a PVC, the PV is not removed immediately. PV removal is postponed until the PV is not bound to a PVC any more.
@@ -112,6 +119,11 @@ When the [Storage Protection beta feature](/docs/tasks/administer-cluster/pvc-pr
=======
When the [Storage Object in Use Protection beta feature](/docs/tasks/administer-cluster/pvc-protection/) is enabled, if a user deletes a PVC in active use by a pod, the PVC is not removed immediately. PVC removal is postponed until the PVC is no longer actively used by any pods.
>>>>>>> Storage Protection was renamed to Storage Object in Use Protection (#7576)
||||||| merged common ancestors
When the [Storage Object in Use Protection beta feature](/docs/tasks/administer-cluster/pvc-protection/) is enabled, if a user deletes a PVC in active use by a pod, the PVC is not removed immediately. PVC removal is postponed until the PVC is no longer actively used by any pods.
=======
When the [Storage Object in Use Protection beta feature](/docs/tasks/administer-cluster/storage-object-in-use-protection/) is enabled, if a user deletes a PVC in active use by a pod, the PVC is not removed immediately. PVC removal is postponed until the PVC is no longer actively used by any pods, and also if admin deletes a PV that is bound to a PVC, the PV is not removed immediately. PV removal is postponed until the PV is not bound to a PVC any more.
>>>>>>> add pv protection description (#7620)
You can see that a PVC is protected when the PVC's status is `Terminating` and the `Finalizers` list includes `kubernetes.io/pvc-protection`:
docs/tasks/administer-cluster/pvc-protection.md
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@@ -1,225 +0,0 @@
---
reviewers:
- msau42
- jsafrane
title: Storage Object in Use Protection
---
{% capture overview %}
{% assign for_k8s_version="v1.10" %}{% include feature-state-beta.md %}
Persistent volume claims (PVCs) that are in active use by a pod can be protected from pre-mature removal.
{% endcapture %}
{% capture prerequisites %}
- The Storage Object in Use Protection feature is enabled in a version of Kubernetes in which it is supported.
{% endcapture %}
{% capture steps %}
## Storage Object in Use Protection feature used for PVC Protection
The example below uses a GCE PD `StorageClass`, however, similar steps can be performed for any volume type.
Create a `StorageClass` for convenient storage provisioning:
```yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: slow
provisioner: kubernetes.io/gce-pd
parameters:
type: pd-standard
```
Verification scenarios follow below.
### Scenario 1: The PVC is not in active use by a pod
- Create a PVC:
```yaml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: slzc
spec:
accessModes:
- ReadWriteOnce
storageClassName: slow
resources:
requests:
storage: 3.7Gi
```
- Check that the PVC has the finalizer `kubernetes.io/pvc-protection` set:
```shell
$ kubectl describe pvc slzc
Name: slzc
Namespace: default
StorageClass: slow
Status: Bound
Volume: pvc-bee8c30a-d6a3-11e7-9af0-42010a800002
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed=yes
pv.kubernetes.io/bound-by-controller=yes
volume.beta.kubernetes.io/storage-provisioner=kubernetes.io/gce-pd
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 4Gi
Access Modes: RWO
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ProvisioningSucceeded 2m persistentvolume-controller Successfully provisioned volume pvc-bee8c30a-d6a3-11e7-9af0-42010a800002 using kubernetes.io/gce-pd
```
- Delete the PVC and check that the PVC (not in active use by a pod) was removed successfully.
### Scenario 2: The PVC is in active use by a pod
- Again, create the same PVC.
- Create a pod that uses the PVC:
```yaml
kind: Pod
apiVersion: v1
metadata:
name: app1
spec:
containers:
- name: test-pod
image: k8s.gcr.io/busybox:1.24
command:
- "/bin/sh"
args:
- "-c"
- "date > /mnt/app1.txt; sleep 60 && exit 0 || exit 1"
volumeMounts:
- name: path-pvc
mountPath: "/mnt"
restartPolicy: "Never"
volumes:
- name: path-pvc
persistentVolumeClaim:
claimName: slzc
```
- Wait until the pod status is `Running`, i.e. the PVC becomes in active use.
- Delete the PVC that is now in active use by a pod and verify that the PVC is not removed but its status is `Terminating`:
```shell
Name: slzc
Namespace: default
StorageClass: slow
Status: Terminating (since Fri, 01 Dec 2017 14:47:55 +0000)
Volume: pvc-803a1f4d-d6a6-11e7-9af0-42010a800002
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed=yes
pv.kubernetes.io/bound-by-controller=yes
volume.beta.kubernetes.io/storage-provisioner=kubernetes.io/gce-pd
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 4Gi
Access Modes: RWO
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ProvisioningSucceeded 52s persistentvolume-controller Successfully provisioned volume pvc-803a1f4d-d6a6-11e7-9af0-42010a800002 using kubernetes.io/gce-pd
```
- Wait until the pod status is `Terminated` (either delete the pod or wait until it finishes). Afterwards, check that the PVC is removed.
### Scenario 3: A pod starts using a PVC that is in Terminating state
- Again, create the same PVC.
- Create a first pod that uses the PVC:
```yaml
kind: Pod
apiVersion: v1
metadata:
name: app1
spec:
containers:
- name: test-pod
image: k8s.gcr.io/busybox:1.24
command:
- "/bin/sh"
args:
- "-c"
- "date > /mnt/app1.txt; sleep 600 && exit 0 || exit 1"
volumeMounts:
- name: path-pvc
mountPath: "/mnt"
restartPolicy: "Never"
volumes:
- name: path-pvc
persistentVolumeClaim:
claimName: slzc
```
- Wait until the pod status is `Running`, i.e. the PVC becomes in active use.
- Delete the PVC that is now in active use by a pod and verify that the PVC is not removed but its status is `Terminating`:
```shell
Name: slzc
Namespace: default
StorageClass: slow
Status: Terminating (since Fri, 01 Dec 2017 14:47:55 +0000)
Volume: pvc-803a1f4d-d6a6-11e7-9af0-42010a800002
Labels: <none>
Annotations: pv.kubernetes.io/bind-completed=yes
pv.kubernetes.io/bound-by-controller=yes
volume.beta.kubernetes.io/storage-provisioner=kubernetes.io/gce-pd
Finalizers: [kubernetes.io/pvc-protection]
Capacity: 4Gi
Access Modes: RWO
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ProvisioningSucceeded 52s persistentvolume-controller Successfully provisioned volume pvc-803a1f4d-d6a6-11e7-9af0-42010a800002 using kubernetes.io/gce-pd
```
- Create a second pod that uses the same PVC:
```
kind: Pod
apiVersion: v1
metadata:
name: app2
spec:
containers:
- name: test-pod
image: gcr.io/google_containers/busybox:1.24
command:
- "/bin/sh"
args:
- "-c"
- "date > /mnt/app1.txt; sleep 600 && exit 0 || exit 1"
volumeMounts:
- name: path-pvc
mountPath: "/mnt"
restartPolicy: "Never"
volumes:
- name: path-pvc
persistentVolumeClaim:
claimName: slzc
```
- Verify that the scheduling of the second pod fails with the below warning:
```
Warning FailedScheduling 18s (x4 over 21s) default-scheduler persistentvolumeclaim "slzc" is being deleted
```
- Wait until the pod status of both pods is `Terminated` or `Completed` (either delete the pods or wait until they finish). Afterwards, check that the PVC is removed.
{% endcapture %}
{% capture discussion %}
{% endcapture %}
{% include templates/task.md %}