How to use volumes in workflow clusters - Container Service for Kubernetes

This topic describes how to mount volumes to workflow clusters and then use the volumes.

Usage notes

You can use Object Storage Service (OSS) volumes and File Storage NAS (NAS) volumes in workflow clusters.

Use OSS volumes

Use the following sample code to create an OSS volume.

For more information, see Mount a statically provisioned ossfs 1.0 volume. To create other types of volumes, replace the corresponding parameters.

Click to view YAML content

apiVersion: v1
kind: Secret
metadata:
  name: oss-secret
  namespace: default
stringData:
  akId: <yourAccessKey ID> # Replace with your AccessKey ID. 
  akSecret: <yourAccessKey Secret> # Replace with your AccessKey secret. 
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-oss
  labels:
    alicloud-pvname: pv-oss
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  csi:
    driver: ossplugin.csi.alibabacloud.com
    volumeHandle: pv-oss   # Specify the name of the persistent volume (PV). 
    nodePublishSecretRef:
      name: oss-secret
      namespace: default
    volumeAttributes:
      bucket: <your bucket name> # Replace with your bucket name. 
      url: "oss-<your region id>-internal.aliyuncs.com" # Replace <your region id> with the region ID of your OSS bucket. For example, if your OSS bucket is created in the China (Beijing) region, the region ID is oss-cn-beijing-internal.aliyuncs.com. 
      otherOpts: "-o umask=022 -o max_stat_cache_size=1000000 -o allow_other"
      path: "/"  # The root directory of the OSS bucket. You can also specify a subdirectory of the OSS bucket. Example: testdir/testdir1.
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-oss
  namespace: default
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 5Gi
  selector:
    matchLabels:
      alicloud-pvname: pv-oss

Optional parameters:

You can configure custom parameters in the -o *** -o *** format for the OSS volume, such as -o umask=022 -o max_stat_cache_size=1000000 -o allow_other.

umask: Modify the permission mask of files in OSSFS. For example, if you set umask=022, the permission mask of files in OSSFS changes to 755. By default, the permission mask of files uploaded by using the OSS SDK or console is 640 in OSSFS. Therefore, we recommend that you use the umask command when you want to split reads and writes.
max_stat_cache_size: Specify the file metadata cache capacity to define the maximum number of file metadata cached. Default: 100,000 entries (~40MB memory).
Metadata caching significantly accelerates file traversal and read operations. However, modifications made through alternative methods, such as OSS, SDK, console, and ossutil, may lead to outdated metadata. For strong data consistency requirements, set this value to 0 to disable metadata caching.
allow_other: Allow other users to access the mounted directory. However, these users cannot access the files in the directory.

For more information about other parameters, see Options supported by ossfs.

Use the following sample code to create a workflow to use the OSS volume:

Click to view YAML content

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: volumes-existing-
  namespace: default
spec:
  entrypoint: volumes-existing-example
  volumes:
  # Pass my-existing-volume as an argument to the volumes-existing-example template.
  # Same syntax as k8s Pod spec.
  - name: workdir
    persistentVolumeClaim:
      claimName: pvc-oss

  templates:
  - name: volumes-existing-example
    steps:
    - - name: generate
        template: whalesay
    - - name: print
        template: print-message

  - name: whalesay
    container:
      image: docker/whalesay:latest
      command: [sh, -c]
      args: ["echo generating message in volume; cowsay hello world | tee /mnt/vol/hello_world.txt"]
      volumeMounts:
      - name: workdir
        mountPath: /mnt/vol

  - name: print-message
    container:
      image: alpine:latest
      command: [sh, -c]
      args: ["echo getting message from volume; find /mnt/vol; cat /mnt/vol/hello_world.txt"]
      volumeMounts:
      - name: workdir
        mountPath: /mnt/vol

Use NAS volumes

Use the following sample code to create a statically provisioned NAS volume:

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apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-nas
  labels:
    alicloud-pvname: pv-nas
spec:
  capacity:
    storage: 100Gi
  accessModes:
    - ReadWriteMany
  csi:
    driver: nasplugin.csi.alibabacloud.com
    volumeHandle: pv-nas   # Specify the name of the PV. 
    volumeAttributes:
      server: "<your nas filesystem id>.cn-beijing.nas.aliyuncs.com"
      path: "/"
  mountOptions:
  - nolock,tcp,noresvport
  - vers=3
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc-nas
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 100Gi
  selector:
    matchLabels:
      alicloud-pvname: pv-nas

Use the following sample code to create a workflow to use the NAS volume.

Click to view YAML content

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: volumes-existing-
  namespace: default
spec:
  entrypoint: volumes-existing-example
  volumes:
  # Pass my-existing-volume as an argument to the volumes-existing-example template.
  # Same syntax as k8s Pod spec.
  - name: workdir
    persistentVolumeClaim:
      claimName: pvc-nas

  templates:
  - name: volumes-existing-example
    steps:
    - - name: generate
        template: whalesay
    - - name: print
        template: print-message

  - name: whalesay
    container:
      image: docker/whalesay:latest
      command: [sh, -c]
      args: ["echo generating message in volume; cowsay hello world | tee /mnt/vol/hello_world.txt"]
      volumeMounts:
      - name: workdir
        mountPath: /mnt/vol

  - name: print-message
    container:
      image: alpine:latest
      command: [sh, -c]
      args: ["echo getting message from volume; find /mnt/vol; cat /mnt/vol/hello_world.txt"]
      volumeMounts:
      - name: workdir
        mountPath: /mnt/vol