Cloud Identity and Access Management (Cloud IAM) provides predefined roles that give granular access to specific Google Cloud resources and prevent unwanted access to other resources.
Cloud IAM also provides the ability to create customized Cloud IAM roles. You can create a custom Cloud IAM role with one or more permissions and then grant that custom role to users. Cloud IAM provides a UI and API for creating and managing custom roles.
This topic does not provide a comprehensive list of all the Cloud IAM permissions you can include in your custom roles. To check whether a specific permission is supported in custom roles, see Support level for permissions in custom roles.
Before you begin
- Read the IAM Overview of basic Cloud IAM concepts.
- Read about the available IAM predefined roles.
- Understand the IAM best practices for least privilege.
In Cloud IAM, you don't directly grant users permissions. Instead, you grant them roles, which bundle one or more permissions. There are three kinds of roles in Cloud IAM: primitive roles, predefined roles, and custom roles.
Primitive roles include three roles that existed prior to the introduction of Cloud IAM: Owner, Editor, and Viewer.
Predefined roles are created and maintained by Google. Their permissions are automatically updated as necessary, such as when new features or services are added to Google Cloud.
Custom roles are user-defined, and allow you to bundle one or more supported permissions to meet your specific needs. Custom roles are not maintained by Google; when new permissions, features, or services are added to Google Cloud, your custom roles will not be updated automatically.
When you create a custom role, you must choose an organization or project to create it in. You can then grant the custom role on the organization or project, as well as any resources within that organization or project.
You create a custom role by combining one or more of the available Cloud IAM permissions. Permissions allow users to perform specific actions on Google Cloud resources. In the Cloud IAM world, permissions are represented in the form:
For example, the
compute.instances.list permission allows a user
to list the Google Compute Engine instances they own, while
compute.instances.stop allows a user to stop a VM.
Permissions usually, but not always, correspond 1:1 with REST methods. That is,
each Google Cloud service has an associated permission for each
REST method that it has. To call a method, the caller needs that permission.
For example, the caller of
topic.publish() needs the
You can only grant a custom role within the project or organization in which you created it. You cannot grant custom roles on other projects or organizations, or on resources within other projects or organizations.
Required permissions and roles
To create a custom role, a caller must have the
Users who are not owners, including organization administrators, must be
assigned either the Organization Role Administrator role
roles/iam.organizationRoleAdmin) or the IAM Role Administrator role
roles/iam.roleAdmin). The IAM Security Reviewer role
roles/iam.securityReviewer) enables the ability to view custom roles but not
administer them. To learn how to grant these roles, see Granting, changing, and
The custom roles user interface is in the Google Cloud Console under IAM Roles. It is only available to users who have permissions to create or manage custom roles. By default, only project owners can create new roles. Project owners can control access to this feature by granting IAM Role Administrator role to others on the same project; for organizations, only Organization Administrators can grant the Organization Role Administrator role.
The administrative roles are described in more detail below.
Organization Role Administrator role
If you have an organization associated with your GCP account, the Organization Role Administrator role enables you to administer all custom roles in your organization. This role can only be granted at the organization level. Only Organization Administrators can grant the Organization Role Administrator role.
The following table lists the permissions in the Organization Role Administrator role:
Role Administrator role
The Role Administrator role enables you to administer all custom roles for a project. Use this role if you do not have an organization. This role can only be granted at the project level by project or organization owners.
The following table lists the permissions in the Role Administrator role:
Custom roles lifecycle
There are a few concepts that apply when deciding how to model, create, and manage your custom roles.
Before you decide to create a custom role, check whether the service has a predefined role—or a combination of multiple predefined roles—that meets your needs. For a complete list of predefined roles, as well as the permissions that are included in each predefined role, see the predefined roles reference.
If there is no predefined role—or combination of predefined roles—that meets your needs, you can create a custom role that includes only the permissions you need to grant. For details, see Creating and managing custom roles.
Unsupported or unavailable permissions
Some permissions might not be visible to you or usable in a custom role. For example, a permission might not be available for use in custom roles if the service is in beta, or if you have not enabled the API for the service.
To check whether you can use a specific permission in custom roles, see Support level for permissions in custom roles. To check which permissions you can use with a specific resource, see Viewing the available permissions for a resource.
Some permissions are effective only when granted in pairs. For example, to
update a Cloud IAM policy, you must use the
read-modify-write pattern. As a result, to update a policy,
you almost always need the
getIamPolicy permission for that service and
resource type, in addition to the
To make sure your custom roles are effective, you can create custom roles based on predefined roles with similar permissions. The predefined roles can help you see which permissions are typically used in combination.
To learn how to create a custom role based on a predefined role, see Creating and managing custom roles.
Naming the role
Roles have both an ID and a title. The role ID is a unique identifier for the role. The role title appears in the list of roles in the Cloud Console.
Role IDs must be unique within the project or organization in which you created the role. This ensures that the role's full ID, which includes its project or organization, is unique. Role IDs can be up to 64 characters long and can contain uppercase and lowercase alphanumeric characters, underscores, and periods.
You cannot change role IDs, so choose your role IDs carefully. You can delete a custom role, but you can't create a new custom role with the same full ID until after the 37-day deletion process has completed. For more information about the deletion process, see Deleting a custom role.
The title for a custom role does not have to be unique. Therefore, the Cloud Console could display more than one custom role with the same title. To avoid confusion, use unique and descriptive titles for your custom roles. Also, consider indicating in the role title if the role is an organization-level role or a project-level role.
Role titles can be up to 100 bytes long and can contain uppercase and lowercase alphanumeric characters and symbols. You can change role titles at any time.
Consider updating the role description after editing a custom role, and include both the date it was modified and a summary of the intended purpose for the role. Descriptions can be up to 256 characters long and comprised of uppercase and lowercase alphanumeric characters and symbols.
Testing and deploying
Custom roles include a
role.stage property. Initially, set the stage to
ALPHA to indicate that the role is in early development and not ready for
production. Then, allow a small set of members of your organization to use
the role in a few sample use cases.
When the members are happy with the newly created custom role, change the
role.stage property to
GA. In general, if your custom role
references permissions for services that are in Beta, you should mark it
GA, until the service is out of Beta.
Job functions and product functionality are constantly evolving. Keeping custom roles up-to-date and following the principle of least privilege requires maintenance effort.
For example, when a released service gets new Beta features, those API methods become publicly available and the permissions are automatically added to the corresponding primitive and predefined roles. Your custom roles for that service do not inherit those new permissions, so users assigned to those custom roles may report that they cannot access the new Beta features. At that point, you could choose to add them, or perhaps create a separate custom role to only grant certain users access to those Beta features.
While Google may update an existing predefined role by adding (or removing) permissions, we do not modify custom roles based on the predefined roles. Custom roles are flat lists of permissions; a custom role has no link to the predefined roles it may have been based on.
If your custom role is based on any predefined roles, we recommend listing those roles in the custom role's description field. Doing this makes it easier for you to check whether you should update your custom role based on changes to a predefined role. The Cloud Console automatically puts that information in the description when it creates a new custom role. To learn how to update a custom role's description, see Editing an existing custom role.
Refer to the permissions change log to determine what roles and permissions have changed recently.
Disabling custom roles
If you no longer wish for people in the your organization to use the role,
role.stage property to
DEPRECATED, and optionally set the
deprecation_message to let users know what alternative roles should be used or
where to get more information. You should also make sure that you don't have any
policies in your organization that might still be referencing the deprecated
When you're sure that the role can be disabled, call
disable this role.
- Some predefined roles contain permissions that are not permitted in custom roles. To check whether you can use a specific permission in a custom role, see Support level for permissions in custom roles.
resourcemanager.projects.listpermission is only supported for organization-level custom roles—it is not permitted in project-level custom roles. When you copy a predefined role that includes the
resourcemanager.projects.listpermission into a new project-level custom role, one of the following messages will be displayed:
- Cloud Console: The following warning message is displayed:
"Not applicable for project-level custom roles". The
resourcemanager.projects.listpermission will be automatically unselected from the list of included permissions, and you can proceed with creating the role.
- Cloud SDK gcloud command-line tool: The following error message is
INVALID_ARGUMENT: Permission resourcemanager.projects.list is not valid. The custom role will not be created until you first remove the
resourcemanager.projects.listpermission from the role definition and try the operation again.
- Google Cloud APIs: The following error message is returned:
Permission resourcemanager.projects.list is not valid, along with an HTTP 400 error code and a status of
INVALID_ARGUMENT. The custom role will not be created until you first remove the
resourcemanager.projects.listpermission from the role definition and try the operation again.
- Cloud Console: The following warning message is displayed: "Not applicable for project-level custom roles". The
Learn how to create custom roles.