- About this article
- In short
- Positioning within Google Cloud
- Difference between Role and Permission
- Resource hierarchy and inheritance
- Practical examples by user type
- How should Microsoft-experienced users understand this?
- APIs, CLI, and Authentication
- Safe Experimentation
- Key security considerations
- Billing, accounts, and projects
- Official Google information
- What should you do next?
- Papanda TRY: Visualize Principal -> Role -> Resource
- What kind of service is this, ultimately?
About this article
This article was created using an automated generation workflow utilizing generative AI.
Based on official Google Cloud Identity and Access Management (IAM) documentation, this guide organizes the fundamentals of access management—determining who gets what role and within which scope—for beginners. It also covers the project hierarchy, roles, permissions, and the principle of least privilege.
Information Verification Date: 2026-09-19
In short
IAM (Identity and Access Management) is the mechanism in Google Cloud that manageswho can do what to which resources. It becomes easier to understand if you think of a Principal as "who," a Role as a "set of allowed actions," and a Permission as an "individual operation right."
Positioning within Google Cloud
| Perspective | IAM |
|---|---|
| Primary Category | Google Cloud / Security, Identity, and Access Control |
| Main Objective | Restrict access to cloud resources to only necessary personnel and processes |
| Components | An access management infrastructure that binds Principals and Roles to Resources |
| Commonly Used With | Organization, Folder, Project, Service Account, and individual Cloud services |
| Primary users | IT administrators, security officers, cloud operators, and developers |
flowchart LR P[Principal<br/>ユーザー・グループ・Service Account等] --> B[Role Binding] R[Role<br/>Permissionの集合] --> B B --> X[Resource<br/>Organization / Folder / Project] X --> S[Compute / Storage / BigQuery等]
Difference between Role and Permission
A permission is the minimum unit that allows a specific operation, while a role is a collection of multiple permissions. Typically, a role suited to the purpose is assigned to a principal.
Roles include Basic roles with broad privileges, Predefined roles provided by Google for each service, and Custom roles created by organizations. Beginners should avoid easily using overly broad Basic roles and adopt the practice of searching for Predefined roles that match their use case for better security.
Resource hierarchy and inheritance
Google Cloud has a hierarchy consisting of Organization -> Folder -> Project -> Resources of individual services. Since allow policies set on upper-level containers can affect lower-level ones, policies in higher layers must also be checked when investigating effective access.
Practical examples by user type
General users and administrative staff
"Being able to log in" and "being able to view cloud data" are different. Even with an account, you may not be able to operate target resources without an IAM role.
IT administrators
Organize the necessary roles for each department, operations team, or automated process, and assign them to the appropriate scope, such as a project or folder. It is also important to maintain operational processes that allow for reviewing privileges upon transfers or the completion of outsourcing.
Developers
Applications and CI/CD pipelines often use non-human identities such as Service Accounts. Instead of reusing a developer's high privileges for the application, grant only the roles necessary for the workload.
How should Microsoft-experienced users understand this?
| Google Cloud | Similar concepts in Microsoft Azure | Commonalities / Differences |
|---|---|---|
| IAM | Azure RBAC | The concept of assigning roles to principals to control operations on resources is similar |
| Principal | User / Group / Service Principal, etc. | Naming conventions and identity infrastructure structures differ |
| Organization / Folder / Project | Management Group / Subscription / Resource Group environment | The hierarchies do not have a strict one-to-one mapping |
| Service Account | Managed Identity / Service Principal environment | Authentication methods and key management designs differ |
For those experienced with Azure RBAC, thinking of it as "Google Cloud's version of resource access control" makes it easier to grasp, but it is best to review Google Cloud's resource hierarchy and role architecture first.
APIs, CLI, and Authentication
IAM can be managed not only through the Google Cloud Console but also via REST APIs, client libraries, and the gcloud CLI. When calling Google Cloud APIs programmatically, you can use authentication methods suited to your execution environment, such as Application Default Credentials (ADC).
Because permission modifications have a significant impact, early examples for beginners prioritize read operations over modifications.
Safe Experimentation
gcloud iam roles describe roles/viewer
What to check? roles/viewer Check the role information such as .
What happens upon success? The role title, description, and included permissions are displayed.
What do you understand by changing a single location?By checking another role name in the official Google Role list and replacing it, you can compare how permissions differ for each role. Do not guess non-existent role names; verify them in the official list.
Key security considerations
Least privilege: Allow only necessary operations.
Verify permission inheritance from upper hierarchies as well.
Avoid using overly broad permissions for daily operations over the long term; consider temporary and auditable access methods as needed.
Do not store service account private keys in public GitHub repositories.
Do not resolve IAM changes by simply adding permissions until errors disappear.
In addition to allow policies, IAM includes mechanisms for granular access control such as deny policies, IAM conditions, principal access boundaries, and Privileged Access Manager. Consult official documentation when the need arises.
Billing, accounts, and projects
IAM is the access management infrastructure for Google Cloud resources. Design not only IAM settings but also Google Cloud accounts, the organization/folder/project structure, and the billing and permissions of target services collectively.
Official Google information
What should you do next?
In a test project, list the three items "Principal / Role / Resource" and read and verify the current access settings in the Google Cloud Console. If changes are necessary, search the official role list for predefined roles that match your purpose and consider them.
Papanda TRY: Visualize Principal -> Role -> Resource
Read a dummy IAM policy JSON in PowerShell and display principals, roles, and resources in three columns. Make it a daily audit-only code that does not automatically modify permissions and flags broad roles like Owner or Editor as "Requires Review".
What kind of service is this, ultimately?
IAM isthe foundational access management system in Google Cloud that determines "who is allowed to do what". It is used to grant necessary Roles to necessary Principals only within the required Resource scope.
