Permissions Management

If you need to grant your enterprise personnel permission to access your DCS resources, use Identity and Access Management (IAM). IAM provides identity authentication, fine-grained permissions management, and access control. IAM helps you secure access to your cloud resources. If your 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 cloud resources. For example, if you want some software developers in your enterprise to be able to use DCS resources but do not want them to be able to delete DCS instances or perform any other high-risk operations, you can create IAM users and grant permission to use DCS instances 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 identity 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.

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 Identity and Access Management User Guide.

Role/Policy-based Authorization

DCS 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.

DCS is a project-level service deployed for specific regions. When you set Scope to Region-specific projects and select the specified projects in the specified regions , the users only have permissions for DCS instances in the selected projects. If you set Scope to All resources, the users have permissions for DCS instances in all region-specific projects. When accessing DCS instances, the users need to switch to the authorized region.

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

**Table 2** System-defined permissions for DCS
Role/Policy Name	Description	Type	Dependencies
DCS FullAccess	All permissions for DCS. Users with these permissions can perform all operations on DCS instances.	System-defined policy	None
DCS UserAccess	Common user permissions for DCS, excluding permissions for creating, modifying, deleting DCS instances and modifying instance specifications.	System-defined policy	None
DCS ReadOnlyAccess	Read-only permissions for DCS. Users with these permissions can only view DCS data.	System-defined policy	None
DCS Administrator	Administrator permissions for DCS. Users with these permissions can operate and use all DCS instances.	System-defined role	Server Administrator and Tenant Guest roles, which must be attached in the same project as the DCS Administrator role

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

**Table 3** Common operations supported by system-defined permissions
Operation	DCS FullAccess	DCS UserAccess	DCS ReadOnlyAccess	DCS Administrator
Modifying instance configuration parameters	√	√	×	√
Deleting background tasks	√	√	×	√
Web CLI	√	√	×	√
Modifying instance running status	√	√	×	√
Expanding instance capacity	√	×	×	√
Changing instance passwords	√	√	×	√
Modifying DCS instances	√	×	×	√
Performing a master/standby switchover	√	√	×	√
Backing up instance data	√	√	×	√
Analyzing big keys or hot keys	√	√	×	√
Creating DCS instances	√	×	×	√
Deleting instance backup files	√	√	×	√
Restoring instance data	√	√	×	√
Resetting instance passwords	√	√	×	√
Migrating instance data	√	√	×	√
Downloading instance backup data	√	√	×	√
Deleting DCS instances	√	×	×	√
Querying instance configuration parameters	√	√	√	√
Querying instance restoration logs	√	√	√	√
Querying instance backup logs	√	√	√	√
Querying DCS instances	√	√	√	√
Querying instance background tasks	√	√	√	√
Querying all instances	√	√	√	√
Operating slow queries	√	√	√	√

Identity Policy-based Authorization

DCS supports identity policy-based authorization. Table 4 lists all the system-defined identity policies for DCS. 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 DCS
Identity Policy Name	Description	Type
DCSServiceLinkedAgencyPolicy	Agency permissions required by DCS for migrating faulty instances. No other operations are involved.	System-defined identity policy
DCSReadOnlyAccessPolicy	Read-only permissions for DCS.	System-defined identity policy
DCSUserAccessPolicy	Common user permissions for DCS, excluding permissions for creating, modifying, deleting DCS instances and modifying instance specifications.	System-defined identity policy
DCSFullAccessPolicy	Full permissions for DCS.	System-defined identity policy

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

**Table 5** Common operations supported by system-defined policies
Operation	DCSReadOnlyAccessPolicy	DCSUserAccessPolicy	DCSFullAccessPolicy
Modifying instance configuration parameters	×	√	√
Deleting background tasks	×	√	√
Web CLI	×	√	√
Modifying instance running status	×	√	√
Expanding instance capacity	×	×	√
Changing instance passwords	×	√	√
Modifying DCS instances	×	×	√
Performing a master/standby switchover	×	√	√
Backing up instance data	×	√	√
Analyzing big keys or hot keys	×	√	√
Creating DCS instances	×	×	√
Deleting instance backup files	×	√	√
Restoring instance data	×	√	√
Resetting instance passwords	×	√	√
Migrating instance data	×	√	√
Downloading instance backup data	×	√	√
Deleting DCS instances	×	×	√
Querying instance configuration parameters	√	√	√
Querying instance restoration logs	√	√	√
Querying instance backup logs	√	√	√
Querying DCS instances	√	√	√
Querying instance background tasks	√	√	√
Querying all instances	√	√	√
Operating slow queries	√	√	√