Help Center/ Cloud Search Service/ API Reference/ Permissions and Supported Actions/ Introduction
Updated on 2025-11-18 GMT+08:00
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Introduction

You can use Identity and Access Management (IAM) for fine-grained permissions management of your CSS resources. If your HUAWEI IDaccount does not need individual IAM users, you can skip this section.

With IAM, you can control access to specific Huawei Cloud resources. IAM supports role/policy-based authorization and identity policy-based authorization.

The following table describes the main differences.

Table 1 Differences between role/policy-based and identity policy-based authorization

Name

Core Relationship

Permissions

Authorization Method

Description

Role/Policy-based authorization

User-permission-authorization scope
  • System-defined roles
  • System-defined policies
  • Custom policies

Assigning roles or policies to principals

To authorize a user, you need to add it to a user group first and then specify the scope of authorization. It provides a limited number of condition keys and cannot meet the requirements of fine-grained permissions control. This method is suitable for small and medium enterprises.

Identity policy-based authorization

User-policy
  • System-defined identity policies
  • Custom identity policies
  • Assigning identity policies to principals
  • Attaching identity policies to principals

You can authorize a user by directly attaching an identity policy to them. You can customize policies and attach them to specified users. Identity policies allow you to perform refined access control more efficiently and flexibly. However, this model is more complex and requires higher personnel expertise. It is more suitable for large and medium enterprises.

Assume that you want to grant IAM users permission to create ECSs in CN North-Beijing4 and OBS buckets in CN South-Guangzhou. With role/policy-based authorization, the administrator needs to create two custom policies and assign both to the IAM users. With identity policy-based authorization, the administrator only needs to create one custom identity policy and configure the condition key g:RequestedRegion for the policy, and then attach the policy to the principals or grant the principals the access permissions to the specified regions. Identity policy-based authorization is more flexible than role/policy-based authorization.

Policies/Identity policies and actions in the two authorization scenarios are not interoperable. You are advised to use the identity policy-based authorization model.

If you use IAM users to call an API, the IAM users must be granted the required permissions. The permissions required for calling an API are determined by the actions supported by the API. Only users who have been granted permissions allowing the actions can call the API successfully.

Assume that an IAM user wants to call an API to create a snapshot. With policy-based authorization, the IAM user must be granted the permissions allowing for action css:snapshot:create. With identity policy-based authorization, the IAM user must be granted the permissions allowing for action iam:agencies:pass.