If you need to control resource access for your personnel, Identity and Access Management (IAM) is a good choice for fine-grained permissions management. IAM provides identity authentication, permissions management, and access control, helping you securely access your cloud resources.

With IAM, you can create IAM users for your employees, and assign permissions to the users to control their access to specific resource types. For example, if you need to grant some users the permissions to view TMS resources, but do not want these users to delete predefined tags, you can create users using IAM and assign TMS ReadOnlyAccess permissions to these users.

If your account does not require IAM for permissions management, you can skip this section.

IAM can be used free of charge. You pay only for the resources in your account. For more information about IAM, see IAM Service Overview.

TMS Permissions

New IAM users do not have any permissions assigned by default. You need to first add them to one or more groups and 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.

TMS is a global service deployed for all regions. When you set the authorization scope to Global services, users have permission to access TMS resources in all regions.

You can grant permissions by using roles and policies.

Roles: A coarse-grained authorization strategy provided by IAM to assign permissions based on users' job responsibilities Only a limited number of service-level roles are available for authorization. When using roles to grant permissions, you must also assign other roles which the permissions depend on to take effect. Roles are not ideal for fine-grained authorization and least privilege access.
Policies: A fine-grained authorization strategy that defines permissions required to perform operations on specific cloud resources under certain conditions. This type of authorization is more flexible and is ideal for least privilege access. The administrator can restrict a user to only specified operations on TMS using IAM policies. For example, if the user is granted a fine-grained permission to only view predefined tags, the user cannot perform other operations on predefined tags (such as creating or deleting predefined tags) with this permission. A majority of fine-grained policies contain permissions for specific APIs. For the API actions supported by TMS, see the section "Permissions Policies and Supported Actions" in the Tag Management Service API Reference.

Table 1 lists all TMS system-defined policies and roles. Some TMS policies depend on the policies of other services to take effect. When you assign TMS permissions to users, you also assign dependent policies for the TMS permissions to take effect.

**Table 1** TMS system-defined permissions
Role/Policy Name	Description	Type	Dependencies
TMS FullAccess	Full permissions for TMS.	System-defined policy	-
TMS ReadOnlyAccess	Read-only permissions for TMS.	System-defined policy	-
TMS Administrator	Full permissions for TMS. Users with these permissions can query, create, delete, import, or export predefined tags, and create, delete, modify, or query resource tags.	System-defined role	Dependent on the following policies: Tenant Guest: a global/project-level policy that grants read-only permissions for all cloud services (except IAM). Server Administrator: A project-level policy, which must be assigned in the same project as the TMS Administrator policy. Tenant Administrator: A global/project-level policy that grants permissions of all cloud service administrators (except the IAM administrator permissions). IMS Administrator: a project-level policy, which must be assigned in the same project as the TMS Administrator policy AutoScaling Administrator: a project-level policy, which must be assigned in the same project as the TMS Administrator policy VPC Administrator: a project-level policy, which must be assigned in the same project as the TMS Administrator policy VBS Administrator: a project-level policy, which must be assigned in the same project as the TMS Administrator policy

Table 2 lists the common operations supported by TMS system-defined permissions.

**Table 2** Common operations supported by system-defined permissions
Operation	TMS FullAccess	TMS ReadOnlyAccess	TMS Administrator
Querying the cloud resource list	Supported (permissions of corresponding services for querying resources required)	Supported (permissions of corresponding services for querying resources required)	Supported (Tenant Guest required)
Creating a key	Supported	Not supported	Supported (Tenant Guest required)
Viewing resource tags	Supported	Supported	Supported (Tenant Guest required)
Creating resource tags	Supported (permissions of corresponding services for creating tags required)	Not supported	Supported (Tenant Guest and corresponding project policies of cloud resources required. For example, if you need to manage VPC tags, select Tenant Guest in the same project.)
Modifying resource tags	Supported (permissions of corresponding services for creating, deleting, and viewing tags required)	Not supported	Supported (Tenant Guest and corresponding project policies of cloud resources required. For example, if you need to manage VPC tags, select Tenant Guest in the same project.)
Deleting resource tags	Supported (permissions of corresponding services for deleting tags required)	Not supported	Supported (Tenant Guest and corresponding project policies of cloud resources required. For example, if you need to manage VPC tags, select Tenant Guest in the same project.)
Querying predefined tags	Supported	Supported	Supported
Creating predefined tags	Supported	Not supported	Supported
Deleting predefined tags	Supported	Not supported	Supported
Exporting predefined tags	Supported	Supported	Supported
Importing predefined tags	Supported	Not supported	Supported

If predefined permissions cannot meet your requirements, you can create custom policies. Custom policies allow you to perform fine-grained access control flexibly. For details about how to create a custom policy, see Creating a Custom Policy. For details about TMS example custom policies, see Custom Policies.

The following table lists fine-grained actions and dependencies for TMS.

**Table 3** TMS fine-grained actions
Action Name	Description	Dependencies	Scenario
tms:predefineTags:list	Grants permissions to view predefined tags	None	Viewing or querying predefined tags
tms:predefineTags:create	Grants permissions to create predefined tags.	tms:predefineTags:list	Creating predefined tags
tms:predefineTags:delete	Grants permissions to delete predefined tags.	tms:predefineTags:list	Deleting predefined tags
tms:predefineTags:update	Grants permissions to update predefined tags	tms:predefineTags:list	Modifying predefined tags (Currently, this action can only be called through the API. This action is not required for any feature on TMS console.)
tms:resourceTags:create	Grants permissions to tag resources.	tms:resources:list Permissions of corresponding services required for creating tags	Adding tags to resources
tms:resourceTags:delete	Grant permissions to remove tags from resources	tms:resourceTags:list Permissions of corresponding services required for deleting tags	Removing resource tags
tms:tagKeys:list	Grants permissions to query tag keys	None	Viewing tag keys (Currently, this action can only be called through the API. This action is not required for any feature on TMS console.)
tms:tagValues:list	Grants permissions to query tag values	None	Viewing tag values (Currently, this action can only be called through the API. This action is not required for any feature on TMS console.)
tms:resourceTags:list	Grants permissions to query tags	None (permissions of corresponding services for querying tags required)	Viewing tags and the number of tags
tms:resources:list	Grants the permissions to view resources	None (permissions of corresponding services for querying resources required)	Searching for cloud resources

If you need to perform operations on tags of cloud resources on TMS console, you must have related permissions for viewing, creating, and deleting resource tags and required permissions for the services to which the resources belong. Modify a resource tag involves a process of deleting the old tag and then creating a new tag (with the same tag key but different tag values). So, to modify a cloud resource tag, you must have both related TMS permissions and service permissions to delete and create tags.

For system-defined permissions: If you need to add or delete tags for ECS resources on TMS console, both TMS FullAccess permissions and ECS FullAccess permissions are required.
For custom permissions: If you need to view ECS resources and tags on the TMS console, not only tms:resourceTags:list permissions, but ecs:servers:getTags and ecs:servers:get permissions are required.

For details about all system-defined permissions of services supported by IAM, see Permissions. For more information about fine-grained permissions of each service, see corresponding documentations of each service.

Permissions

TMS Permissions

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