Implementing GCP Organization Policy Constraints

Implementing GCP Organization Policy Constraints

Overview

The GCP Organization Policy Service provides centralized and programmatic control over cloud resources. Organization policies configure constraints that restrict one or more Google Cloud services, enforced at organization, folder, or project levels. They improve security by blocking external IPs, requiring encryption, and minimizing unauthorized access. Changes can take up to 15 minutes to propagate.

When to Use

Trigger phrases:

• "implementing gcp organization policy constraints"

• "Implement GCP Organization Policy constraints to enforce security guardrails acr"

• When deploying or configuring implementing gcp organization policy constraints capabilities in your environment

• When establishing security controls aligned to compliance requirements

• When building or improving security architecture for this domain

• When conducting security assessments that require this implementation

Prerequisites

• GCP Organization with Organization Administrator role
• gcloud CLI configured and authenticated
• Terraform or gcloud for policy management
• Organization Policy Administrator IAM role (roles/orgpolicy.policyAdmin)

Core Concepts

This section covers core concepts for implementing gcp organization policy constraints.

• Ensure all prerequisites are met before proceeding
• Follow the documented workflow steps in sequence
• Record results and any anomalies encountered during this phase

Constraint Types

1. List Constraints: Allow or deny specific values (e.g., allowed regions)
2. Boolean Constraints: Enable or disable a capability (e.g., disable serial port access)
3. Custom Constraints: User-defined rules targeting specific resource fields (Preview)

Policy Inheritance

Policies inherit from the lowest ancestor with an enforced policy. If no ancestor has a policy, Google's managed default behavior applies.

Essential Security Constraints

This section covers essential security constraints for implementing gcp organization policy constraints.

• Ensure all prerequisites are met before proceeding
• Follow the documented workflow steps in sequence
• Record results and any anomalies encountered during this phase

Restrict VM External IP Addresses

# Deny external IP addresses on all VMs
gcloud resource-manager org-policies set-policy \
  --organization=ORGANIZATION_ID \
  policy.yaml

policy.yaml:

constraint: constraints/compute.vmExternalIpAccess
listPolicy:
  allValues: DENY

Restrict Resource Locations

gcloud org-policies set-policy \
  --organization=ORGANIZATION_ID \
  location-policy.yaml

location-policy.yaml:

constraint: constraints/gcp.resourceLocations
listPolicy:
  allowedValues:
    - "in:us-locations"
    - "in:eu-locations"

Disable Default Service Account Creation

constraint: constraints/iam.automaticIamGrantsForDefaultServiceAccounts
booleanPolicy:
  enforced: true

Require OS Login for SSH

constraint: constraints/compute.requireOsLogin
booleanPolicy:
  enforced: true

Disable Serial Port Access

constraint: constraints/compute.disableSerialPortAccess
booleanPolicy:
  enforced: true

Enforce Uniform Bucket-Level Access

constraint: constraints/storage.uniformBucketLevelAccess
booleanPolicy:
  enforced: true

Restrict Public IP on Cloud SQL

constraint: constraints/sql.restrictPublicIp
booleanPolicy:
  enforced: true

Disable Service Account Key Creation

constraint: constraints/iam.disableServiceAccountKeyCreation
booleanPolicy:
  enforced: true

Terraform Implementation

resource "google_organization_policy" "restrict_vm_external_ip" {
  org_id     = var.org_id
  constraint = "constraints/compute.vmExternalIpAccess"

  list_policy {
    deny {
      all = true
    }
  }
}

resource "google_organization_policy" "restrict_locations" {
  org_id     = var.org_id
  constraint = "constraints/gcp.resourceLocations"

  list_policy {
    allow {
      values = ["in:us-locations", "in:eu-locations"]
    }
  }
}

resource "google_organization_policy" "require_os_login" {
  org_id     = var.org_id
  constraint = "constraints/compute.requireOsLogin"

  boolean_policy {
    enforced = true
  }
}

resource "google_folder_organization_policy" "dev_folder_external_ip" {
  folder     = google_folder.dev.name
  constraint = "constraints/compute.vmExternalIpAccess"

  list_policy {
    allow {
      values = ["projects/dev-project/zones/us-central1-a/instances/bastion-host"]
    }
  }
}

Dry-Run Testing

Use Policy Intelligence tools to test changes before enforcement:

# Create a dry-run policy to monitor impact
gcloud org-policies set-policy \
  --organization=ORGANIZATION_ID \
  dry-run-policy.yaml

dry-run-policy.yaml:

constraint: constraints/compute.vmExternalIpAccess
listPolicy:
  allValues: DENY
dryRunSpec: true

# Check violations against dry-run policy
gcloud org-policies list-custom-constraints \
  --organization=ORGANIZATION_ID

Custom Constraints

# custom-constraint.yaml
name: organizations/ORGANIZATION_ID/customConstraints/custom.disableGKEAutoUpgrade
resourceTypes:
  - container.googleapis.com/NodePool
methodTypes:
  - CREATE
  - UPDATE
condition: "resource.management.autoUpgrade == true"
actionType: DENY
displayName: Deny GKE auto-upgrade on node pools
description: Prevents enabling auto-upgrade on GKE node pools for controlled upgrades

gcloud org-policies set-custom-constraint custom-constraint.yaml

Monitoring and Compliance

This section covers monitoring and compliance for implementing gcp organization policy constraints.

• Ensure all prerequisites are met before proceeding
• Follow the documented workflow steps in sequence
• Record results and any anomalies encountered during this phase

List active policies

gcloud org-policies list --organization=ORGANIZATION_ID

Describe a specific policy

gcloud org-policies describe constraints/compute.vmExternalIpAccess \
  --organization=ORGANIZATION_ID

Audit policy violations with Cloud Asset Inventory

gcloud asset search-all-resources \
  --scope=organizations/ORGANIZATION_ID \
  --query="policy:constraints/compute.vmExternalIpAccess"

Recommended Baseline Policies

When NOT to Use

• You need to test the implementation (use performing-* skills)
• Task is about configuring existing tools (use configuring-* skills)
• You need to analyze security events (use analyzing-* skills)
• Task is about building detection rules (use building-* skills)
• You don't have access to the target environment
• Task requires vendor-specific expertise (consult vendor docs)

Red Flags

• Performing actions without explicit written authorization from the asset owner
• Testing against production systems without a defined scope and rules of engagement
• Modifying cloud IAM policies or security groups without approval
• Exposing cloud credentials or secrets in logs or reports
• Running scans that generate excessive API calls and trigger billing alerts

Verification

• All steps executed successfully against a test environment before production use
• Output documented with screenshots or logs demonstrating expected behavior
• Cloud resource changes reverted or documented as intentional
• IAM policies reviewed for least-privilege compliance after testing
• No residual test resources left running (cost and security check)

References

• GCP Organization Policy Constraints: https://docs.google.com/resource-manager/docs/organization-policy/org-policy-constraints
• GCP Policy Intelligence: https://cloud.google.com/policy-intelligence
• CIS GCP Foundations Benchmark

Process

1. Analyze the task requirements
2. Apply domain expertise
3. Verify output quality

Anti-Rationalization Table