The Storage Admin (roles/storage.admin) role provides full control over Cloud Storage resources. This includes all necessary permissions to manage both buckets (e.g., create, delete, list, set IAM policies) and the objects (files) within them. Using this predefined role adheres to the Google-recommended practice of applying the principle of least privilege. It grants the required permissions scoped specifically to the Cloud Storage service, unlike the overly broad Project Editor basic role. This role is the most suitable for colleagues who need comprehensive control over buckets and files without granting them permissions for other services in the project.

A. Project Editor: This is a basic role that grants broad permissions across most Google Cloud services, violating the principle of least privilege.

C. Storage Object Admin: This role grants permissions to manage objects (files) but lacks the necessary permissions to create, delete, or configure buckets.

D. Storage Object Creator: This role is highly restrictive, only allowing users to create objects. It does not permit managing objects or buckets.

1. Google Cloud Documentation

"Cloud Storage IAM roles": The table in this document explicitly states that the roles/storage.admin role provides "Full control of Cloud Storage resources

" which encompasses both buckets and objects. In contrast

roles/storage.objectAdmin is described as having "Full control of Cloud Storage objects

" which does not include bucket management.

Source: Google Cloud

Cloud Storage Documentation

"IAM roles for Cloud Storage".

2. Google Cloud Documentation

"Understanding roles": This guide explains the different types of roles. It recommends using predefined roles over basic roles (like Editor) to grant only the necessary permissions. "Whenever possible

we recommend that you grant predefined roles instead of basic roles. Predefined roles provide finer-grained access control and help you follow the principle of least privilege."

Source: Google Cloud

IAM Documentation

"Understanding roles"

Section: "Role types".

3. Google Cloud Documentation

"Using IAM permissions": This document reinforces the best practice of using the most limited predefined role that meets requirements. "Follow the principle of least privilege... When choosing a predefined role

pick one that contains the minimum set of permissions that your user needs."

Source: Google Cloud

IAM Documentation

"Granting

changing

and revoking access to resources"

Section: "Best practices".