Granting IAM Users Under an Account the Access to a Bucket and the Resources in It

Scenario

This topic describes how to grant IAM users the permissions to access OBS buckets and resources in them.

The following describes how to grant the permissions to upload and download objects in a bucket. If you need to configure other specified permissions, configure the corresponding permissions in the bucket policy and IAM permissions.

Recommended Configuration

To grant permissions to IAM users under an account, you need to configure both bucket policies and IAM permissions.

For example, to allow IAM user A of account A to access bucket B of account B, you need to:

1. Configure a bucket policy that allows IAM user A to access bucket B.
2. Configure IAM permissions for account A to allow IAM user A to access bucket B.

Configuration Precautions

After the configuration is complete, the authorized IAM user can upload and download objects through APIs or SDKs. In addition, the user can upload and download objects by mounting external buckets on OBS Browser+. To add external buckets, the ListBucket permission is also required. Currently, access to buckets of other accounts is not allowed on OBS Console.

Procedure 1: The Bucket Owner Configures a Bucket Policy.

The bucket owner or a user who has the permission to configure bucket policies needs to configure a bucket policy that allows IAM users under an account to perform specified operations on the bucket.

In this example, account B (owner of bucket B) configures a bucket policy that allows IAM user A of account A to upload objects to and download objects from bucket B of account B.

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 Custom policy and click Create Custom Policy.
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. Set Principal to Other account. Account ID: Enter the ID of the account which you want to grant permissions to. You can obtain it from the My Credentials page of the account or the IAM user. The ID of account A is used as an example here. IAM User ID: Enter the ID of the IAM user under the authorized account. You can obtain the ID on the My Credentials page of the IAM user. The wildcard character (*) is supported, indicating that the setting takes effect for all IAM users under the account. The ID of IAM user A under account A is used as an example here. User Policy: Select Include specified users. Parameters under Resources: Resource: Select both Current bucket and Object in bucket. Object in bucket: Select Specified objects. For one object, enter object name. For a set of objects, enter object name prefix + *, * + object name suffix, or *. Resource Policy: Select Include specified resources. Parameters under Actions: GetObject GetObjectVersion PutObject (Optional) ListBucket: Select this operation if you need to use OBS Browser+ to add external buckets. To configure other specified operation permissions on objects, select the corresponding actions. For details about the actions supported by OBS, see Action/NotAction. Operation Strategy: Select Include selected.

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

Procedure 2: The Account Grants Permissions to IAM Users Under It.

The account (not the bucket owner) needs to grant permissions to its IAM users to allow them perform specified operations on the bucket. (The allowed operations must be the same as those allowed in the bucket policy.)

In this example, account A needs to grant IAM user A the permissions to upload objects to and download objects from bucket B of account B.

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	Select Allow. Select Object Storage Service (OBS). Select the actions to be authorized. ReadOnly > obs:bucket:ListBucketVersions and obs:object:GetObjectVersion ReadWrite > obs:object:PutObject ListOnly > obs:bucket:ListBucket (Select this operation if you need to use OBS Browser+ to add external buckets.) If you need to configure permissions on other actions, select the corresponding actions. For details, see Bucket-Related Actions and Object-Related Actions. Choose Specific > object to specify an object resource. The specified object or object set must be consistent with the bucket policy. Select Any if the resource set in the bucket policy is *. If the resource specified in the bucket policy is a specified object or a set of objects, you need to specify the object or the set of objects the same as that in the bucket policy through the resource path. [Format] obs:*:*:object:bucket name/object name Select Any as the bucket policy in this example is set to *. Choose Specific > bucket > Specify resource path to specify bucket resources. Click Add Resource Path and enter the name of the authorized bucket in the Path text box, for example, example-bucket. The complete path of the resource is as follows: OBS:*:*:bucket:example-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.