This topic provides answers to some frequently asked questions about Apsara File Storage NAS (NAS) volumes.

The system prompts chown: Operation not permitted

Symptom:

The system prompts chown: Operation not permitted when I mount a NAS file system.

Cause:

Your container does not have permissions to use the specified NAS file system.

Solution:

Launch the container with root privileges.

What do I do if the task queue of alicloud-nas-controller is full and PVs cannot be created when I use a dynamically provisioned NAS volume?

Symptom:

When you use a dynamically provisioned NAS volume, if the speed of subdirectory creation is faster than the speed of subdirectory deletion, the task queue of alicloud-nas-controller may be full and therefore PVs cannot be created.

Cause:

The reclaimPolicy parameter is set to Delete and the archiveOnDelete parameter is set to false in the configuration of the StorageClass that mounts the dynamically provisioned NAS volume.

Solution:

Set archiveOnDelete to true. This way, when a PV is deleted, only the name of the mounted subdirectory in the NAS file system is modified. The files in the subdirectory are not deleted.

You must delete these files yourself. For example, you can configure a node to automatically delete files in the root directory by schedule, or start multiple pods to concurrently delete files of specific formats in subdirectories.

Why does it require a long time to mount a NAS volume?

Symptom:

It requires a long time to mount a NAS volume.

Cause:

If the following conditions are met, the chmod or chown operation is performed when volumes are mounted, which increases the time consumption.

  • The AccessModes parameter is set to ReadWriteOnce in the PV and PVC templates.
  • The securityContext.fsgroup parameter is set in the application template.

Solution:

  • If the securityContext.fsgroup parameter is set in the application template, delete the fsgroup parameter in the securityContext section.
  • If you want to configure the user ID (UID) and mode of the files in the mounted directory, you can manually mount the directory to an Elastic Compute Service (ECS) instance. You can then perform chown and chmod operations through a CLI and provision the NAS volume through the CSI plug-in. For more information about how to provision NAS volumes through the CSI plug-in, see Mount a statically provisioned NAS volume or Mount a dynamically provisioned NAS volume.
  • For clusters of Kubernetes 1.20 or later, you can set the fsGroupChangePolicy parameter to OnRootMismatch. This way, the chmod or chown operation is performed only when the pod that uses the volume is first started. For more information, see Set the security context for a container.