QuotaPath volumes-阿里云帮助中心

You can use the ProjectQuota feature of a file system, such as Ext4, on a local disk to control capacity quotas at the directory level. The Container Storage Interface (CSI) plugin manages the lifecycle of QuotaPath volumes, including creation, quota management, and mounting. This topic describes how to use QuotaPath volumes.

Prerequisites

The Logical Volume Manager (LVM) CSI plugin is deployed. For more information, see Step 2: Deploy the plugin and provisioner components.

Differences among QuotaPath, HostPath, and LVM

HostPath, LVM, and QuotaPath all allow pods to access host storage. Each method has distinct features:

HostPath partitions storage by directory. Multiple directories share the space, I/O, and other resources of the same underlying storage device.
LVM virtualizes a storage device and then splits it into multiple volumes. Each volume has an independent storage capacity.
QuotaPath uses the quota feature of a file system to partition storage by directory. Each directory has an independent storage capacity.

Features

Lifecycle management for QuotaPath volumes: automatic creation, deletion, mounting, and unmounting.
Expansion for QuotaPath volumes.
Node local storage management: automatic operations and maintenance (O&M) for the QuotaPath root directory.
Cluster capacity awareness for QuotaPath volumes.

Notes

QuotaPath is a local storage type. It is not suitable for high availability (HA) data scenarios.
O&M for the QuotaPath root directory and local storage capacity awareness are optional features that are not yet available.
If you start a container in privileged mode, the quota limit does not take effect. This behavior is a characteristic of the Ext4 file system.

QuotaPath usage examples

When you use CSI-Provisioner to automatically create a PersistentVolume (PV), note the following:

Specify the `rootPath` parameter in the StorageClass.
If you want to create the PV on a specific node, add the volume.kubernetes.io/selected-node: nodeName label to the PersistentVolumeClaim (PVC).

Create a StorageClass.

Create a file named alicloud-local-quota.yaml with the following content.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: alicloud-local-quota
parameters:
  volumeType: QuotaPath
  rootPath: /mnt/quota
provisioner: localplugin.csi.alibabacloud.com
reclaimPolicy: Delete
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer

Parameter	Description
volumeType	The local storage type. In this example, the storage type is QuotaPath.
rootPath	Optional. The name of the directory where the QuotaPath is located.

Run the following command to create the StorageClass.
```
kubectl create -f alicloud-local-quota.yaml
```

Create a PVC.
1. Create a file named csi-quota.yaml with the following content.
  By default, the CSI plugin uses /mnt/quotapath.namespacex.x as the root directory for QuotaPath. All PVs and their subdirectories are created in this directory.
  To specify a custom parent directory for QuotaPath, add the volume.kubernetes.io/selected-storage: /mnt/xxx annotation to the PVC.
```
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: csi-quota
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 2Gi
  storageClassName: alicloud-local-quota
```
2. Run the following command to create the PVC.
```
kubectl create -f csi-quota.yaml
```

Create an application from a template.

Create a file named web-quota.yaml with the following content.

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web-quota
spec:
  selector:
    matchLabels:
      app: nginx
  serviceName: "nginx"
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
        - name: disk-ssd
          mountPath: /data
      volumes:
        - name: "disk-ssd"
          persistentVolumeClaim:
            claimName: csi-quota

Run the following command to create the application.
```
kubectl create -f web-quota.yaml
```

Check the application status.

Run the following command to view the pod information.

kubectl get pod |grep quota

Expected output:

NAME          READY   STATUS    RESTARTS   AGE
web-quota-0   1/1     Running   0          16s

Run the following command to view the PVC information.

kubectl get pvc

Expected output:

NAME        STATUS   VOLUME                CAPACITY   ACCESS MODES   STORAGECLASS           AGE
csi-quota   Bound    local-f4b129a5-****   2Gi        RWO            alicloud-local-quota   48s

Run the following command to view the PV information.

kubectl get pv |grep quota

Expected output:

NAME                  CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM               STORAGECLASS           REASON   AGE
local-f4b129a5-****   2Gi        RWO            Delete           Bound    default/csi-quota   alicloud-local-quota            66s

Run the following commands to view the pod mount details.

kubectl exec -ti web-quota-0 sh
df |grep data

Expected output:

Filesystem  1K-blocks  Used Available Use% Mounted on
/dev/vdd    2097152       4   2097148   1% /data

Run the following command to list the directories in /data.

ls /data

Expected output:

lost+found

Run the following commands to create and view a test directory in /data.

touch /data/test
ls /data

Expected output:

lost+found test

Expand the volume.

Run the following command to view the PVC information.

kubectl get pvc

Expected output:

NAME        STATUS   VOLUME                CAPACITY   ACCESS MODES   STORAGECLASS           AGE
csi-quota   Bound    local-f4b129a5-****   2Gi        RWO            alicloud-local-quota   42s

Run the following command to expand the PVC to 3 GiB.

kubectl patch pvc csi-quota -p '{"spec":{"resources":{"requests":{"storage":"3Gi"}}}}'

Expected output:

persistentvolumeclaim/csi-quota patched

Run the following command to view the PVC information.

kubectl get pvc

Expected output:

NAME        STATUS   VOLUME                CAPACITY   ACCESS MODES   STORAGECLASS           AGE
csi-quota   Bound    local-f4b129a5-****   3Gi        RWO            alicloud-local-quota   4m30s

Run the following commands to verify that the volume is expanded to 3 GiB.

kubectl exec -ti web-quota-0 sh
df |grep data

Expected output:

Filesystem  1K-blocks  Used Available Use% Mounted on
/dev/vdd    3145728       4   3145724   1% /data