GCP IAM Roles and Permissions – Manage Access Securely

Gcp Kajal November 29, 2025 2 mins read

This guide explains GCP IAM roles and permissions, helping you control access to cloud resources securely.

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🧠 1. Introduction

In Google Cloud Platform (GCP), Identity and Access Management (IAM) determines who can do what on your cloud resources.
Configuring IAM correctly is crucial for:

  • Security

  • Compliance

  • Operational governance

  • Preventing unauthorized access

This guide walks through IAM essentials, role types, and best practices for secure access management.

🔑 2. IAM Core Concepts

Principals

Entities requesting access:

  • Users

  • Groups

  • Service accounts (machine identities)

Resources

Items within GCP:

  • Projects

  • Compute Engine VMs

  • Cloud Storage buckets

  • BigQuery datasets

  • And more

Roles

A set of permissions that define what actions can be taken.

Policies

Bindings that connect:
Principal → Role → Resource

📂 3. Types of IAM Roles

Role Type Description Examples
Basic Roles Broad, legacy roles Viewer, Editor, Owner
Predefined Fine-grained service-specific roles Compute Admin, Storage Viewer
Custom User-created roles with exact perms Custom Compute Backup Role

Notes:

  • Basic roles are too permissive — avoid them for production.

  • Predefined roles are the recommended choice.

  • Custom roles are perfect for specialized workloads.

🖥️ 4. Assigning IAM Roles (Console Method)

  1. Go to IAM & Admin → IAM

  2. Click Grant Access

  3. Enter the principal (user email or service account)

  4. Select one or more roles

  5. Click Save

This method is user-friendly and great for administrators.

💻 5. Assigning IAM Roles Using gcloud CLI

 
gcloud projects add-iam-policy-binding my-project \ --member="user:admin@example.com" \ --role="roles/compute.admin"

CLI is ideal for scripting, automation, and CI/CD pipelines.

🛡️ 6. Best Practices for IAM Security

✔ Use least privilege — assign only what is needed
✔ Prefer predefined roles over basic roles
✔ Audit IAM roles and access regularly
✔ Use service accounts for app and automation access
✔ Enable Cloud Audit Logs to track changes
✔ Rotate service account keys periodically
✔ Apply IAM at the lowest resource level

Implementing these reduces the risk of privilege misuse and improves compliance posture.

🖼️ 7. Visual Guide (Recommended Images)

Include visuals such as:

  • Screenshot: IAM role assignment page in GCP

  • Diagram: Principal → Role → Resource

  • Infographic comparing Basic vs Predefined vs Custom roles

These help explain concepts more clearly to readers.

🏁 8. Conclusion

IAM is the foundation of secure cloud management in GCP. With the right mix of predefined roles, least privilege access, and continuous auditing, you can maintain a secure and compliant environment.

In the next blog, we’ll dive into monitoring VM performance and logs using GCP’s built-in monitoring tools.

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K
Kajal

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