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IAM Roles & Permissions

gcp

Predefined and custom collections of fine-grained permissions.

IAM & SECURITY
Google Cloud Platform

Predefined and custom collections of fine-grained permissions.

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What is IAM Roles & Permissions?

In Google Cloud IAM, permissions are never granted directly to users; instead, permissions are bundled into Roles. GCP provides hundreds of curated Predefined Roles maintained by Google (e.g. `roles/bigquery.dataEditor`) and allows security architects to author Custom Roles with specific granular permission strings (e.g. `compute.instances.start`).

Decision Guide: When to Choose This Service

When to Use IAM Roles & Permissions

Use Predefined Roles for standard Google-maintained service capabilities, and Custom Roles when you need strict least-privilege tailoring for specialized compliance mandates.

When NOT to Use (Recommended Alternatives)

Do NOT use legacy Basic Roles (Owner, Editor, Viewer) for automated pipelines or production environments.

Core Architectural Pillars

Permission Syntax

`service.resource.verb` (e.g. `bigquery.tables.getData`).

Basic Roles (Primitive)

Owner, Editor, Viewer (Avoid in production).

Predefined Roles

Google-managed service roles (e.g. `roles/run.developer`, `roles/pubsub.publisher`).

Custom Roles

User-created collections of specific permissions scoped to a Project or Organization.

IAM Recommender

Machine-learning powered tool that analyzes 90 days of actual user API activity and suggests downsizing over-privileged roles to exact matching predefined roles.