IAM-based Permissions Management

If you need to assign different permissions to employees in your enterprise to access your DRS resources, IAM is a good choice for fine-grained permissions management. IAM provides identity authentication, permissions management, and access control, helping you to securely access your Huawei Cloud resources. If your Huawei Cloud account does not require IAM for permissions management, you can skip this section.

IAM is a free service. You only pay for the resources in your account.

With IAM, you can control access to specific Huawei Cloud resources. For example, if you want some software developers in your enterprise to be able to use DRS resources but do not want them to be able to delete DRS resources or perform any other high-risk operations, you can create IAM users and grant permission to use DRS resources but not permission to delete them.

IAM supports role/policy-based authorization and identity policy-based authorization.

The following table describes the differences between these two authorization models.

**Table 1** Differences between role/policy-based and identity policy-based authorization
Authorization Model	Core Relationship	Permissions	Authorization Method	Scenario
Role/Policy	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-sized enterprises.
Identity policy	User-policy	System-defined policies Custom identity policies	Assigning identity policies to principals Attaching identity policies to principals	You can authorize a user by attaching an identity policy to it. User-specific authorization and a variety of key conditions allow for more fine-grained permissions control. However, this model can be hard to set up. It requires a certain amount of expertise and is suitable for medium- and large-sized enterprises.

Assume that you want to grant IAM users the permissions needed to create DRS tasks 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 attaches the policy to the users or grants the users 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 models are not interoperable. You are advised to use the identity policy-based authorization model. For details about system-defined permissions, see Role/Policy-based Authorization and Identity Policy-based Authorization.

For more information about IAM, see IAM Service Overview.

Role/Policy-based Authorization

DRS supports role/policy-based authorization. New IAM users do not have any permissions assigned by default. You need to first add them to one or more groups and then attach policies or roles to these groups. The users then inherit permissions from the groups and can perform specified operations on cloud services based on the permissions they have been assigned.

DRS is a project-level service deployed in specific physical regions. When you set Scope to Region-specific projects and select the specified projects (for example, ap-southeast-2) in the specified regions (for example, AP-Bangkok), the users only have permissions for resources in the selected projects. If you set Scope to All resources, the users have permissions for resources in all region-specific projects. When accessing DRS, the users need to switch to the authorized region.

Table 2 lists all the system-defined permissions for DRS. System-defined policies in role/policy-based authorization are not interoperable with those in identity policy-based authorization.

**Table 2** System-defined roles and policies supported by DRS
Policy Name/System Role	Description	Type	Dependency
Security Administrator	Security administrator To improve your experience with DRS, add the Security Administrator permission using IAM in case some functions become unavailable, such as scheduled task startup, automatic ending of full-migration tasks, and automatic retry of failed tasks. If the automatic function is unavailable, see Why Cannot Scheduled DRS Tasks Be Started?	System-defined role	None
DRS Administrator	DRS administrator Basic permission, which must be added when DRS is used.	System-defined role	Dependent on the Tenant Guest, Server Administrator, and RDS Administrator roles. Tenant Guest: A project-level role, which must be assigned in the same project. Server Administrator: A project-level role, which must be assigned in the same project. RDS Administrator: A project-level role, which must be assigned in the same project.
DRS FullAccess	Full permissions for DRS	System policy	Dependent on the VPC FullAccess, RDS ReadOnlyAccess, and SMN Administrator, OBS Administrator, and EPS ReadOnlyAccess policies. VPC FullAccess: This parameter needs to be configured when the VPC and subnet are selected. RDS ReadOnlyAccess: This parameter needs to be configured when RDS is selected. SMN Administrator: This parameter needs to be configured when SMN is selected. OBS Administrator: This parameter needs to be configured when bucket information is selected for a backup task. EPS ReadOnlyAccess: This parameter needs to be configured when an enterprise project is selected. For a yearly/monthly task, the following permissions must be configured: BSS Operator or BSS Administrator
DRS ReadOnlyAccess	Read-only permissions for DRS resources.	System policy	Configure the following policies as required: RDS ReadOnlyAccess: This parameter needs to be configured when RDS is selected. SMN Administrator: This parameter needs to be configured when SMN is selected.
DRS FullWithOutDeletePermission	All permissions on DRS except the deletion permission	System Policy	Dependent on the VPC FullAccess, RDS ReadOnlyAccess, and SMN Administrator, and OBS Administrator policies. VPC FullAccess: This parameter needs to be configured when the VPC and subnet are selected. RDS ReadOnlyAccess: This parameter needs to be configured when RDS is selected. SMN Administrator: This parameter needs to be configured when SMN is selected. OBS Administrator: This parameter needs to be configured when bucket information is selected for a backup task. For a yearly/monthly task, the following permissions must be configured: BSS Operator or BSS Administrator

In addition to the preceding permissions, the read permission for the corresponding DB instance is required. For example, if a DDM database is used, configure the DDM ReadOnlyAccess permission for the project. If a DDS database is used, configure the DDS ReadOnlyAccess permission for the project.

Table 3 lists the common operations supported by system-defined permissions for DRS.

**Table 3** Common operations supported by the DRS system policy
Procedure	DRS FullAccess	DRS ReadOnlyAccess	DRS Administrator	DRS FullWithOutDeletePermission
Creating a task	√	x	√	√
Editing a task	√	x	√	√
Deleting a task	√	x	√	x
Starting a task	√	x	√	√
Retrying a task	√	x	√	√
Stopping a task	√	x	√	√

Identity Policy-based Authorization

DRS supports identity policy-based authorization. Table 4 lists all the system-defined identity policies for DRS. System-defined policies in identity policy-based authorization are not interoperable with those in role/policy-based authorization.

**Table 4** System-defined identity policies for DRS
Identity Policy Name	Description	Type	Remarks
DRSAdministratorPolicy	Administrator permissions for DRS.	System-defined identity policy	-
DRSReadOnlyAccessPolicy	Read-only permissions for DRS.	System-defined identity policy	-
DRSFullAccessPolicy	Administrator permissions for DRS. Users granted these permissions can operate and use DRS.	System-defined identity policy	Configure required policies according to the resources you select. VPCFullAccessPolicy: This policy needs to be configured when a VPC and subnet are selected. SMNAdministratorPolicy: This policy needs to be configured when SMN is selected. OBSAdministratorPolicy: This policy needs to be configured when bucket information is selected for a backup task. ReadOnlyAccessPolicy: This policy needs to be configured when an enterprise project is selected.
DRSFullWithOutDeleteAccessPolicy	Full permissions for DRS, except for those for deleting tasks.	System-defined identity policy	Configure required policies according to the resources you select. VPCFullAccessPolicy: This policy needs to be configured when a VPC and subnet are selected. SMNAdministratorPolicy: This policy needs to be configured when SMN is selected. OBSAdministratorPolicy: This policy needs to be configured when bucket information is selected for a backup task. ReadOnlyAccessPolicy: This policy needs to be configured when an enterprise project is selected.

In addition to the above policies, you need to configure read-only policies for DB instances according to the resources you select. For example, if you select an RDS database, you need to configure RDSReadOnlyAccessPolicy. If you select a DDS database, you need to configure DDSReadOnlyAccessPolicy. If you select a DDM database, you need to configure the DDM ReadOnlyAccess permission because DDM does not support the policy-based authorization model.

Table 5 lists the common operations supported by system-defined identity policies for DRS.