What are predefined roles in Google Cloud IAM?

Predefined roles in Google Cloud IAM are specific sets of permissions that Google has created to cater to common use cases and best practices across its various services. These roles encompass standard permissions that align with specific job functions or application needs within Google Cloud, making them widely applicable and easier to manage.

Using predefined roles helps organizations streamline their permission management, as they do not have to create roles from scratch or define permissions individually. Instead, predefined roles come with permissions that have been vetted and recommended based on experiences and best practices from Google Cloud's extensive use. This not only supports the security principle of least privilege but also reduces the administrative overhead associated with custom role management.

The other options refer to concepts that do not accurately depict predefined roles. Custom roles, for example, are the ones that users create for specific needs. Furthermore, while admins can manage roles, predefined roles are not limited to being editable exclusively by them, as they are fixed configurations set by Google. Lastly, predefined roles do not grant unlimited access, as they are designed to provide scoped permissions targeted toward specific functionalities rather than broad, unrestricted access.