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Volcano Engine Function as a Service

Storage

Mounting TOS

veFaaS supports mounting TOS so that you can store data in Volcano Engine TOS buckets. This topic describes how to mount a TOS bucket.

Prerequisites

You have activated Volcano Engine TOS.

You have created a TOS bucket in the region where the function will be deployed. For detailed instructions, see Creating buckets.

You have obtained API access keys that have permission to access TOS. Refer to Access Key management and Creating users and granting permissions permissions for specific operations.

tip

To better manage permissions, we recommend using IAM user keys with minimal authorization. Do not directly use Volcano Engine root user keys or IAM user keys with excessive permissions.

Limits

Each function supports up to 10 TOS mount targets.

When a single function is configured to use multiple TOS mount targets, buckets and bucket subdirectories can be duplicated, but local directories cannot be duplicated.

If a function mounts both FileNAS and TOS, the local directories set for FileNAS and TOS mount targets cannot be duplicated.

Only TOS buckets in the same region as the function can be mounted. After a TOS bucket is mounted, only the internal TOS endpoint can be used as the access address.

Procedure

You can configure a TOS mount target for a function using one of the following methods:

During function creation

When creating the function, configure TOS mounting in the Advanced settings > Storage section. For detailed steps of creating functions, see Creating functions.

After function creation

In the function list, click the name of the function to enter the Function settings page.

On the function settings page, click "Edit" next to storage configuration.

In the "Edit storage settings" panel, enable TOS mounting.

Configure the TOS mount parameters as required and click "Save".

Parameter	Description
AKSK	Enter the Access Key ID and Secret Access Key to authorize veFaaS to use TOS. The access key must have read and write permissions for TOS.
TOS mount	You can add up to 5 TOS mount targets to a function. For each mount target, configure the following items: Bucket: Select the TOS Bucket to mount. Access address: Automatically obtained after selecting the Bucket. Bucket subdirectory: Select the bucket subdirectory the function needs to access. It must start with /. Setting it to / mounts the root directory of the bucket. Local directory: Configure the local directory in the function runtime environment. The local directory must comply with the following rules: It must start with /. It cannot be set to /tmp, /opt/bytefaas, or /opt/tiger/bytefaas/binary. When multiple TOS mount targets are set, the local directories cannot be duplicated. The local directories for FileNAS and TOS mount targets cannot be duplicated. Permission: Select the access permission for the local directory at which the bucket is mounted. read/write permission: Authorizes the function to read and write the local directory. Read-only: Authorizes the function to read the local directory.

What to do next

Release the function

For the storage configuration to take effect, you need to release the function. For details, see Releasing functions.

View details of the mounted TOS bucket

On the "Basic information" tab of the function details page, select the TOS mount card and click the link icon next to the name to navigate to the TOS console, where you can view details of the mounted bucket.

View monitoring metrics of the mounted TOS bucket

On the "Basic information" tab of the function details page, select the TOS mount card and click the monitor icon next to the name to navigate to the Cloud Monitor console, where you can view metrics of the TOS bucket.

Last updated: 2026.08.19 14:06:05