Mount an OSS bucket - Elastic Container Instance - Alibaba Cloud Documentation Center

Object Storage Service (OSS) is a secure, cost-effective, and highly reliable Alibaba Cloud storage service that allows you to store large volumes of unstructured data, such as images and audio and video data. You can use FlexVolume to mount OSS buckets as volumes on a self-managed Kubernetes cluster. You can mount OSS buckets only as statically provisioned volumes. This topic describes how to use a PersistentVolumeClaim (PVC) to mount an OSS bucket as a statically provisioned volume to multiple elastic container instance-based pods.

Prerequisites

A virtual node (VNode) is deployed on a self-managed Kubernetes cluster.
If the self-managed Kubernetes cluster is deployed in a data center, the data center is connected to Alibaba Cloud.

Precautions

OSS is a shared storage service. You can mount an OSS bucket to multiple pods.
You cannot mount OSS buckets as dynamically provisioned volumes. OSS buckets do not support dynamically provisioned persistent volumes (PVs).
We recommend that you store no more than 1,000 files in the mount directory. If you store a large number of files in the mount directory, the OSSFS driver consumes excess memory. This may cause out of memory (OOM) errors in pods.

Procedure

Create an OSS bucket.
1. Log on to the OSS console.
2. Create an OSS bucket.
  For more information, see Create buckets.
Use one of the following methods to grant the permissions to manage OSS buckets:
- Use a RAM role for authorization.
  Create a RAM role and grant the RAM role the permissions to manage OSS buckets. When you create a RAM role, select Alibaba Cloud Service for the Select Trusted Entity parameter, Normal Service Role for the Role Type parameter, and Elastic Compute Service for the Select Trusted Service parameter. When you grant permissions to the RAM role, attach the AliyunOSSFullAccess policy to the RAM role.
  For more information, see Create a RAM role for a trusted Alibaba Cloud service and Grant permissions to a RAM role.
- (Not recommended) Use your AccessKey pair for authorization.
  Obtain your AccessKey ID and AccessKey secret. For more information, see Obtain an AccessKey pair.

Create a PV.

Create a file named pv-oss.yaml and copy the following template content into the file.

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-oss
  labels:
    alicloud-pvname: pv-oss
spec:
  capacity:
    storage: 20Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  flexVolume:
    driver: "alicloud/oss"
    options:
      bucket: "oss-test"
      url: "oss-cn-beijing-internal.aliyuncs.com"
      otherOpts: "-o max_stat_cache_size=0 -o allow_other"
      path: "/"
      ramRole: "<your RAM Role Name>"

In the preceding example, a RAM role is used for authorization. If you want to use your AccessKey pair for authorization, replace ramRole: "<Your RAM role name>" with the following lines:

      akId: "<your AccessKey ID>"
      akSecret: "<your AccessKey Secret>"

The following table describes the parameters in the template.

Parameter	Description
driver	The type of the driver used. In this example, the parameter is set to `alicloud/oss`. This indicates that the FlexVolume plug-in for OSS provided by Alibaba Cloud is used.
bucket	The name of the OSS bucket. You can only mount OSS buckets to pods. You cannot mount the subdirectories or files in OSS buckets to pods.
url	The endpoint of the OSS bucket. If the OSS bucket resides in the same region as the VNode, use the internal endpoint of the OSS bucket. If the OSS bucket resides in a region different from the VNode, use the public endpoint of the OSS bucket.
otherOpts	The custom options that are specified to mount the OSS bucket. Format: `-o * -o *`. Example: `-o max_stat_cache_size=0 -o allow_other`.
path	The path relative to the root directory of the OSS bucket. Default value: `/`.
ramRole	The RAM role that is used for authorization. Specify the parameter if you use a RAM role for authorization.
akId and akSecret	The AccessKey ID and AccessKey secret that are used for authorization. Specify the two parameters if you use your AccessKey pair for authorization.

Run the following command to create a PV:
```
kubectl create -f pv-oss.yaml
```

Create a PVC.

Create a file named ppvc-oss.yaml and copy the following template content into the file.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-oss
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 20Gi
  selector:
    matchLabels:
      alicloud-pvname: pv-oss

Run the following command to create a PVC:
```
kubectl create -f pvc-oss.yaml
```

Mount the OSS bucket to two elastic container instance-based pods.

Create a file named test-oss.yaml and copy the following template content into the file.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: oss-static
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      nodeSelector:    
        k8s.aliyun.com/vnode: "true"
      tolerations:     
      - key: k8s.aliyun.com/vnode
        operator: "Equal"
        value: "true"
        effect: "NoSchedule"
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
        volumeMounts:
          - name: pvc-oss
            mountPath: "/data"
      volumes:
        - name: pvc-oss
          persistentVolumeClaim:
            claimName: pvc-oss

Run the following command to create a Deployment:
```
kubectl create -f test-oss.yaml
```

View the results.

kubectl get pods -o wide

The following command output is expected to return:

NAME                               READY   STATUS    RESTARTS   AGE     IP              NODE                                  NOMINATED NODE   READINESS GATES

test-oss-6bb586ff5-fx9l4           1/1     Running   0          20s     172.16.XX.XX    cn-beijing.vnd-2ze8nd8xcl33t4pa****   <none>           <none>
test-oss-6bb586ff5-lkk8l           1/1     Running   0          22s     172.16.XX.XX    cn-beijing.vnd-2ze8nd8xcl33t4pa****   <none>           <none>

Check the file directories in the pods and verify that the /data mount directory is generated for the OSS bucket. In addition, verify that the files written to one pod are displayed in the other pod. This indicates that the two pods share the OSS bucket.

Mount an OSS bucket as a statically provisioned volume by using FlexVolume