To create a custom role, a caller must possess iam.roles.create permission. By default, the owner of a project or an organization has this permission and can create and manage custom roles.
Users who are not owners, including organization admins, must be assigned either the Organization Role Administrator role, or the IAM Role Administrator role.
To create a new custom role from scratch:
-
Go to the Roles page in the GCP Console.
-
Select your organization from the Organization drop-down.
-
Click Create Role.
-
Enter a Name, a Title, and Description for the role.
-
Click Add Permissions.
-
Select the permissions you want to include in the role and click Add Permissions. Use the All Services and All Typesdrop-downs to filter and select permissions by services and types.
For more info refer to https://cloud.google.com/iam/docs/creating-custom-roles#iam-custom-roles-get-metadata-console