Granting an IAM User the Read/Write Permission for a Bucket

Scenario

This topic describes how to grant an IAM user the read/write permission for an OBS bucket.

Recommended Configuration

You are advised to use bucket policies to grant resource-level permissions to an IAM user.

Configuration Precautions

In this case, the preset template Bucket Read/Write allows specified IAM users to perform all actions excluding the following ones on a bucket and the objects in it:

• DeleteBucket (to delete a bucket)
• PutBucketPolicy (to configure a bucket policy)
• PutBucketAcl (to configure a bucket ACL)

After the configuration is complete, read and write operations (uploading, downloading, and deleting all objects in the bucket) can be performed using APIs or SDKs. However, if you log in to OBS Console or OBS Browser+ to perform those operations, an error is reported indicating that you do not have required permissions. For details, see the error cause.

If you want an IAM user to perform read and write operations on OBS Console or OBS Browser+, configure custom IAM policies by referring to Follow-up Procedure.

After the configuration is complete, it is normal if the system still displays a message indicating that you do not have required permissions, because OBS Console also calls other APIs for advanced settings, but you can still perform the allowed read/write operations.

Procedure

1. In the navigation pane of OBS Console, choose Object Storage.
2. In the bucket list, click the bucket name you want to go to the Objects page.
3. In the navigation pane, choose Permissions > Bucket Policy.
4. On the Bucket Policies page, click Create.
5. Locate the row containing Bucket read and write and click Use Policy Template.
6. Configure parameters for a bucket policy.
   Figure 1 Configuring bucket policy parameters
   

   Table 1 Parameter description

   Parameter	Description
   Policy View	Set this parameter based on your own habits. Visual editor is used here.
   Policy Name	Enter a policy name.
   Policy Content	Select Allow. Parameters under Principal: Principal: Select Current account. Sub-user: Select one or more IAM users to whom you want to grant permissions. User Policy: Select Include specified users. Parameters under Resources: Resource: Select both Current bucket and Object in bucket. Resource Policy: Select Include specified resources.

7. After configuring the required parameters, click Next.
8. Ensure all the configurations are correct and click Create.

Follow-up Procedure

To perform read and write operations on OBS Console or OBS Browser+, you must add the obs:bucket:ListAllMyBuckets (for listing buckets) and obs:bucket:ListBucket (for listing objects in a bucket) permissions to the custom IAM policy.

obs:bucket:ListAllMyBuckets applies to all resources, while obs:bucket:ListBucket applies to the authorized bucket only. Therefore, you need to add two permissions to the policy.

1. Log in to Huawei Cloud and click Console in the upper right corner.
2. On the top menu bar, choose Service List > Management & Deployment > Identity and Access Management. The IAM console is displayed.
3. In the navigation pane, choose Policies.
4. Click Create Custom Policy in the upper right corner.
5. Configure parameters for a custom policy.

   Table 2 Parameters for configuring a custom policy

   Parameter	Description
   Policy Name	Enter a policy name.
   Policy View	Set this parameter based on your own habits. Visual editor is used here.
   Policy Content	[Permission 1] Select Allow. Select Object Storage Service (OBS). Select obs:bucket:ListAllMyBuckets from the actions. Select All for resources. [Permission 2] Select Allow. Select Object Storage Service (OBS). Select obs:bucket:ListBucket from the actions. For Resources, select Specific, and for bucket, select Specify resource path, and click Add Resource Path. Enter the bucket name in the Path text box, indicating that the policy takes effect only for this bucket.
   Scope	The default value is Global services.

6. Click OK. The custom policy is created.
7. Create a user group and assign permissions.

   Add the created custom policy to the user group by following the instructions in the IAM document.

8. Add the IAM user you want to authorize to the created user group by referring to Adding Users to or Removing Users from a User Group.
   

   Due to data caching, it takes about 10 to 15 minutes for a custom policy to take effect after the authorization.