Google Cloud Identity and Access Management (Cloud IAM) provides predefined roles that give granular access to specific Google Cloud Platform 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 who are part of your organization. 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. Learn about the permissions you can apply to a specific service using the links in the More IAM documentation section.
Before you begin
- Read the IAM Overview basic Cloud IAM concepts.
- Read about the available IAM predefined roles.
- Understand the IAM best practices for least privilege.
You don't directly grant users permissions. Instead, you grant them roles, which bundle one or more permissions. Predefined roles are created by Google and we maintain with the most up-to-date permissions required for new features and other changes. Custom roles allow you to bundle one or more of the available permissions to specifically meet your needs. You can create a custom role at the organization level and at the project level.
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 Platform 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 GCP service has an associated set of permissions for each
REST method that it has. To call a method, the caller needs those permissions.
For example, the caller of
topic.publish() needs the
Custom roles can only be created for project-wide or organization-wide use. They cannot be created at the folder level.
Custom roles can only be used to grant permissions in policies for the same project or organization that owns the roles or resources under them. You cannot grant custom roles from one project or organization on a resource owned by a different project or organization.
Required permissions and roles
To create a custom role, a caller must have
Users who are not owners, including organization administrators, must be assigned either the Organization Role Administrator role, or the IAM Role Administrator role. The IAM Security Reviewer role (roles/iam.securityReviewer) enables the ability to view custom roles but not administer them.
The custom roles user interface is in the Cloud Platform 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:
IAM Role Administrator role
The IAM 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.
The following table lists the permissions in the IAM 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, make sure that there is not already an existing predefined role (or set of roles) for the service that meets your needs. You can learn about the permissions applicable to a specific service by following the links in the More IAM documentation section. For a list of the permissions contained in a predefined role, see Getting the role metadata.
If the set of permissions granted with one or more predefined roles is not right for you, you should create a custom role that is based off of one or more predefined roles, and add or delete permissions from it as necessary. The details about how to do this can be found in Creating and Managing Custom Roles.
You should also be aware that some permissions may not be visible to you or useable in a custom role. For example, a permission may 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.
Some permissions are only effective when granted in pairs.
For example, since updating IAM policies requires using the
setIamPolicy almost always requires using the
getIamPolicy so that
you can obtain the etag before updating a policy.
Also, to ensure that the Google Cloud Console works as expected, be aware that
you need to grant permissions for
resourcemanager.projects.list at the appropriate levels. In general, you
should grant list permission on the parent resource, and get permission on the
Naming the role
The ID for a custom role must be unique, but the name property does not have to be.
Therefore, the console could display more than one custom role with the same name. To avoid confusion, use unique and descriptive names for your custom roles.
Choose the ID of your role carefully, because it cannot be changed. You can delete a role, but you can't create a new custom role with the same ID until after the 7-day waiting period during which the deleted role can be un-deleted.
The role name is what is displayed in the console. Choose unambiguous names to prevent confusion for users selecting custom roles in the Console. Also consider indicating which roles are organization-level vs. project-level by putting that in the role name. The role name can be changed at any time.
Always update the role description after editing a custom role, to at least reflect the date it was modified and a summary of the intended job role.
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 they are out of Beta.
Job functions and product functionality are constantly evolving. Keeping custom roles up-to-date and assigned the least privileges necessary 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 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. Since custom roles are flat lists of permissions, there is no link to the Predefined role(s) it may have been based on.
We recommend adding that sort of information to the Description field, so it’s easier to review whether more recent changes to Predefined roles warrant updates. The Cloud Console automatically puts that information in the description when creating a new custom role.
Refer to IAM Permissions Change Log to determine what 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 role.
When you're sure that the role can be disabled, call
disable this role.
- This is a Beta release. The Beta is suitable for testing your custom roles with the specific combinations of permissions that meet your needs. Each service determines its readiness to support custom roles. The IAM Permissions Change Log to discover what permissions have changed for a given service.
Some predefined roles contain deprecated permissions or permissions that are otherwise not permitted in custom roles. A custom role that is based on a predefined role that contains deprecated or restricted permissions will not contain those permissions.
Custom roles created within a project can't list other projects. When you copy a predefined role that includes the
resourcemanager.projects.listpermission into a new custom role, that permission is removed and the following message is displayed:
- Cloud Platform Console: Forbidden Permissions
- Cloud SDK gcloud command-line tool:
More IAM documentation
|IAM Overview||Explains the basic concepts of IAM.|
|Understanding Roles||Explains primitive and curated IAM roles.|
|IAM for Organizations||Explains IAM roles and permissions for the Organizations.|
|IAM for Projects||Explains IAM roles and permissions for projects.|
|IAM for App Engine||Explains IAM roles and permissions for App Engine.|
|IAM for Compute Engine||Explains IAM roles and permissions for Compute Engine.|
|IAM for Cloud Storage||Explains IAM roles and permissions for Cloud Storage.|
|IAM for Cloud BigQuery||Explains IAM roles and permissions for Cloud BigQuery.|
|IAM for Cloud Bigtable||Explains IAM roles and permissions for Cloud Bigtable.|
|IAM for Stackdriver Logging||Explains IAM roles and permissions for Stackdriver Logging.|
|IAM for Cloud Pub/Sub||Explains IAM roles and permissions for Cloud Pub/Sub.|
|IAM for Cloud Dataflow||Explains IAM roles and permissions for Cloud Dataflow.|
|IAM for Stackdriver Debugger||Explains IAM roles and permissions for Stackdriver Debugger.|
|IAM for Cloud Deployment Manager||Explains IAM roles and permissions for Cloud Deployment Manager.|
|IAM for Cloud Datastore||Explains IAM roles and permissions for Cloud Datastore.
Note: Cloud Datastore does not currently support custom roles.
|IAM for Cloud Dataproc||Explains IAM roles and permissions for Cloud Dataproc.|
|IAM for Google Kubernetes Engine||Explains IAM roles and permissions for Google Kubernetes Engine.|
|IAM for Cloud DNS||Explains IAM roles and permissions for Cloud DNS.|
|IAM for Folders||Explains IAM roles and permissions for folders.|
|IAM for Google Genomics||Explains IAM roles and permissions for Google Genomics.|
|IAM for Stackdriver Trace||Explains IAM roles and permissions for Stackdriver Trace.|
|IAM for Cloud Billing API||Explains IAM roles and permissions for Cloud Billing API.|
|IAM for Service Management||Explains IAM roles and permissions for Service Management.|