Manage VPC resources by using custom organization policies

This page shows you how to use Organization Policy Service custom constraints to restrict specific operations on the following Google Cloud resources:

  • compute.googleapis.com/Address
  • compute.googleapis.com/Network
  • compute.googleapis.com/NetworkAttachment
  • compute.googleapis.com/PacketMirroring
  • compute.googleapis.com/Route
  • compute.googleapis.com/ServiceAttachment
  • compute.googleapis.com/Subnetwork
  • networkconnectivity.googleapis.com/InternalRange

To learn more about Organization Policy, see Custom organization policies.

About organization policies and constraints

The Google Cloud Organization Policy Service gives you centralized, programmatic control over your organization's resources. As the organization policy administrator, you can define an organization policy, which is a set of restrictions called constraints that apply to Google Cloud resources and descendants of those resources in the Google Cloud resource hierarchy. You can enforce organization policies at the organization, folder, or project level.

Organization Policy provides built-in managed constraints for various Google Cloud services. However, if you want more granular, customizable control over the specific fields that are restricted in your organization policies, you can also create custom constraints and use those custom constraints in an organization policy.

Policy inheritance

By default, organization policies are inherited by the descendants of the resources on which you enforce the policy. For example, if you enforce a policy on a folder, Google Cloud enforces the policy on all projects in the folder. To learn more about this behavior and how to change it, refer to Hierarchy evaluation rules.

Limitations

Custom constraints are only enforced on the CREATE method for route resources.

Before you begin

  1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

  2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Roles required to select or create a project

    • Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
    • Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

    Go to project selector

  3. Verify that billing is enabled for your Google Cloud project.

  4. Install the Google Cloud CLI.

  5. If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

  6. To initialize the gcloud CLI, run the following command: 

    gcloud init

  7. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Roles required to select or create a project

    • Select a project: Selecting a project doesn't require a specific IAM role—you can select any project that you've been granted a role on.
    • Create a project: To create a project, you need the Project Creator role (roles/resourcemanager.projectCreator), which contains the resourcemanager.projects.create permission. Learn how to grant roles.

    Go to project selector

  8. Verify that billing is enabled for your Google Cloud project.

  9. Install the Google Cloud CLI.

  10. If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

  11. To initialize the gcloud CLI, run the following command: 

    gcloud init
  12. Ensure that you know your organization ID.

Required roles

To get the permissions that you need to manage custom organization policies, ask your administrator to grant you the Organization Policy Administrator (roles/orgpolicy.policyAdmin) IAM role on the organization resource. For more information about granting roles, see Manage access to projects, folders, and organizations.

You might also be able to get the required permissions through custom roles or other predefined roles.

Set up a custom constraint

A custom constraint is defined in a YAML file by the resources, methods, conditions, and actions that are supported by the service on which you are enforcing the organization policy. Conditions for your custom constraints are defined using Common Expression Language (CEL). For more information about how to build conditions in custom constraints using CEL, see the CEL section of Creating and managing custom constraints.

Console

To create a custom constraint, do the following:

  1. In the Google Cloud console, go to the Organization policies page.

    Go to Organization policies

  2. From the project picker, select the project that you want to set the organization policy for.
  3. Click Custom constraint.
  4. In the Display name box, enter a human-readable name for the constraint. This name is used in error messages and can be used for identification and debugging. Don't use PII or sensitive data in display names because this name could be exposed in error messages. This field can contain up to 200 characters.
  5. In the Constraint ID box, enter the name that you want for your new custom constraint. A custom constraint can only contain letters (including upper and lowercase) or numbers, for example custom.disableGkeAutoUpgrade. This field can contain up to 70 characters, not counting the prefix (custom.), for example, organizations/123456789/customConstraints/custom. Don't include PII or sensitive data in your constraint ID, because it could be exposed in error messages.
  6. In the Description box, enter a human-readable description of the constraint. This description is used as an error message when the policy is violated. Include details about why the policy violation occurred and how to resolve the policy violation. Don't include PII or sensitive data in your description, because it could be exposed in error messages. This field can contain up to 2000 characters.
  7. In the Resource type box, select the name of the Google Cloud REST resource containing the object and field that you want to restrict—for example, container.googleapis.com/NodePool. Most resource types support up to 20 custom constraints. If you attempt to create more custom constraints, the operation fails.
  8. Under Enforcement method, select whether to enforce the constraint on a REST CREATE method or on both CREATE and UPDATE methods. If you enforce the constraint with the UPDATE method on a resource that violates the constraint, changes to that resource are blocked by the organization policy unless the change resolves the violation.

    9. Not all Google Cloud services support both methods. To see supported methods for each service, find the service in Supported services.

  9. To define a condition, click Edit condition.
    1. In the Add condition panel, create a CEL condition that refers to a supported service resource, for example, resource.management.autoUpgrade == false. This field can contain up to 1000 characters. For details about CEL usage, see Common Expression Language. For more information about the service resources you can use in your custom constraints, see Custom constraint supported services.
    2. Click Save.
  10. Under Action, select whether to allow or deny the evaluated method if the condition is met.

    11. The deny action means that the operation to create or update the resource is blocked if the condition evaluates to true.

    The allow action means that the operation to create or update the resource is permitted only if the condition evaluates to true. Every other case except ones explicitly listed in the condition is blocked.

  11. Click Create constraint.

    12. When you have entered a value into each field, the equivalent YAML configuration for this custom constraint appears on the right.

gcloud

  1. To create a custom constraint, create a YAML file using the following format: 
    2. name: organizations/ORGANIZATION_ID/customConstraints/CONSTRAINT_NAME
resourceTypes: RESOURCE_NAME
methodTypes:
  - CREATE
    - UPDATE     
condition: "CONDITION"
actionType: ACTION
displayName: DISPLAY_NAME
description: DESCRIPTION

    Replace the following:

  • ORGANIZATION_ID: your organization ID, such as 123456789.
  • CONSTRAINT_NAME: the name that you want for your new custom constraint. A custom constraint can only contain letters (including upper and lowercase) or numbers, for example, custom.createCustomNetworks. This field can contain up to 70 characters.
  • RESOURCE_NAME: the fully qualified name of the Google Cloud resource containing the object and field that you want to restrict. For example, compute.googleapis.com/compute.googleapis.com/Network.
  • CONDITION: a CEL condition that is written against a representation of a supported service resource. This field can contain up to 1000 characters. For example, "resource.autoCreateSubnetworks == false".

    • For more information about the resources available to write conditions against, see Supported resources.

  • ACTION: the action to take if the condition is met. Can only be ALLOW.

    • The allow action means that if the condition evaluates to true, the operation to create or update the resource is permitted. This also means that every other case except the one explicitly listed in the condition is blocked.

  • DISPLAY_NAME: a human-friendly name for the constraint. This field can contain up to 200 characters.
  • DESCRIPTION: a human-friendly description of the constraint to display as an error message when the policy is violated. This field can contain up to 2000 characters.
  • After you have created the YAML file for a new custom constraint, you must set it up to make it available for organization policies in your organization. To set up a custom constraint, use the gcloud org-policies set-custom-constraint command: 
    • gcloud org-policies set-custom-constraint CONSTRAINT_PATH

    Replace CONSTRAINT_PATH with the full path to your custom constraint file. For example, /home/user/customconstraint.yaml.

    After this operation is complete, your custom constraints are available as organization policies in your list of Google Cloud organization policies.

  • To verify that the custom constraint exists, use the gcloud org-policies list-custom-constraints command: 
    • gcloud org-policies list-custom-constraints --organization=ORGANIZATION_ID

    Replace ORGANIZATION_ID with the ID of your organization resource.

    For more information, see Viewing organization policies.

    Enforce a custom organization policy

    You can enforce a constraint by creating an organization policy that references it, and then applying that organization policy to a Google Cloud resource.

    Console

    1. In the Google Cloud console, go to the Organization policies page.

      Go to Organization policies

    2. From the project picker, select the project that you want to set the organization policy for.
    3. From the list on the Organization policies page, select your constraint to view the Policy details page for that constraint.
    4. To configure the organization policy for this resource, click Manage policy.
    5. On the Edit policy page, select Override parent's policy.
    6. Click Add a rule.
    7. In the Enforcement section, select whether this organization policy is enforced or not.
    8. Optional: To make the organization policy conditional on a tag, click Add condition. Note that if you add a conditional rule to an organization policy, you must add at least one unconditional rule or the policy cannot be saved. For more information, see Setting an organization policy with tags.
    9. Click Test changes to simulate the effect of the organization policy. For more information, see Test organization policy changes with Policy Simulator.
    10. To enforce the organization policy in dry-run mode, click Set dry run policy. For more information, see Create an organization policy in dry-run mode.
    11. After you verify that the organization policy in dry-run mode works as intended, set the live policy by clicking Set policy.

    gcloud

    1. To create an organization policy with boolean rules, create a policy YAML file that references the constraint: 
      2. name: projects/PROJECT_ID/policies/CONSTRAINT_NAME
spec:
  rules:
  - enforce: true

dryRunSpec:
  rules:
  - enforce: true

      Replace the following:

    • PROJECT_ID: the project that you want to enforce your constraint on.
    • CONSTRAINT_NAME: the name you defined for your custom constraint. For example, custom.createCustomNetworks.
  • To enforce the organization policy in dry-run mode, run the following command with the dryRunSpec flag: 
    • gcloud org-policies set-policy POLICY_PATH --update-mask=dryRunSpec

    Replace POLICY_PATH with the full path to your organization policy YAML file. The policy requires up to 15 minutes to take effect.

  • After you verify that the organization policy in dry-run mode works as intended, set the live policy with the org-policies set-policy command and the spec flag: 
    • gcloud org-policies set-policy POLICY_PATH --update-mask=spec

    Replace POLICY_PATH with the full path to your organization policy YAML file. The policy requires up to 15 minutes to take effect.

    Test the custom organization policy

    The following example creates a custom constraint that prevents you from creating auto mode VPC networks.

    gcloud

    1. Create a onlyCustomNetwork.yaml constraint file with the following information. Replace ORGANIZATION_ID with your organization ID.

      name: organizations/ORGANIZATION_ID/customConstraints/custom.createOnlyCustomNetwork
resourceTypes: compute.googleapis.com/Network
condition: "resource.autoCreateSubnetworks == false"
actionType: ALLOW
methodTypes: CREATE
displayName: Restrict creation of networks to custom mode networks
description: Only custom mode networks allowed.

    2. Set the custom constraint.

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

    3. Create a onlyCustomNetwork-policy.yaml policy file with the following information. In this example we enforce this constraint at the project level but you might also set this at the organization or folder level. Replace PROJECT_ID with your project ID.

            name: projects/PROJECT_ID/policies/custom.onlyCustomNetwork
      spec:
        rules:
        – enforce: true

    4. Enforce the policy.

      gcloud org-policies set-policy onlyCustomNetwork-policy.yaml

    5. Test the constraint by trying to create an auto mode VPC network.

      gcloud compute networks create vpc1
    --project=PROJECT_ID \
    --subnet-mode=auto

      The output is similar to the following:

      ERROR: (gcloud.compute.networks.create) Could not fetch resource:
- Operation denied by custom org policy: [customConstraints/custom.createOnlyCustomNetwork] : Only custom mode networks allowed.

    Example custom organization policies for common use cases

    This table provides syntax examples for some common custom constraints.

    Description Constraint syntax
    Require networks to have an internal IPv6 range 
    name: organizations/ORGANIZATION_ID/customConstraints/custom.networkInternalIpv6Range
resourceTypes: compute.googleapis.com/Network
condition: "resource.enableUlaInternalIpv6 == true"
actionType: ALLOW
methodTypes: CREATE
displayName: Require networks to have an internal IPv6 range
description: Networks must have a ULA internal IPv6 range configured
    Require subnets to use ranges in 10.0.0.0/8 
    name: organizations/ORGANIZATION_ID/customConstraints/custom.subnetRangeUse10Slash8
resourceTypes: compute.googleapis.com/Subnetwork
condition: "resource.ipCidrRange.startsWith('10.')"
actionType: ALLOW
methodTypes: CREATE
displayName: Require subnets to use ranges in 10.0.0.0/8
description: Subnetwork's primary IPv4 range must come from 10.0.0.0/8
    Require next-hop-ilb routes to be specified by using the IP address instead of the forwarding rule resource name. 
    name: organizations/ORGANIZATION_ID/customConstraints/custom.routeNextHopIlbByIpAddress
resourceTypes: compute.googleapis.com/Route
condition: "!resource.nextHopIlb.contains('forwardingRules')"
actionType: ALLOW
methodTypes: CREATE
displayName: Require defining next-hop-ilb by IP address
description: Next hops that are an internal load balancer must be specified by IP address instead of resource name.
    Require Packet Mirroring to mirror TCP traffic only 
    name: organizations/ORGANIZATION_ID/customConstraints/custom.packetMirroringTcpFilter
resourceTypes: compute.googleapis.com/PacketMirroring
condition: "resource.filter.IPProtocols.size() == 1 && resource.filter.IPProtocols[0] == 'tcp'"
actionType: ALLOW
methodTypes:
  - CREATE
  - UPDATE
displayName: Require policies to mirror TCP protocol only.
description: Packet mirroring must mirror all TCP traffic and no other protocols.

    VPC supported resources

    The following table lists the VPC resources that you can reference in custom constraints.

    Resource Field
    compute.googleapis.com/Address resource.address
    resource.addressType
    resource.description
    resource.ipv6EndpointType
    resource.ipVersion
    resource.name
    resource.network
    resource.networkTier
    resource.prefixLength
    resource.purpose
    resource.subnetwork
    compute.googleapis.com/Network resource.autoCreateSubnetworks
    resource.description
    resource.enableUlaInternalIpv6
    resource.internalIpv6Range
    resource.mtu
    resource.name
    resource.networkFirewallPolicyEnforcementOrder
    resource.peerings.autoCreateRoutes
    resource.peerings.exchangeSubnetRoutes
    resource.peerings.exportCustomRoutes
    resource.peerings.exportSubnetRoutesWithPublicIp
    resource.peerings.importCustomRoutes
    resource.peerings.importSubnetRoutesWithPublicIp
    resource.peerings.name
    resource.peerings.network
    resource.peerings.peerMtu
    resource.peerings.stackType
    resource.routingConfig.bgpAlwaysCompareMed
    resource.routingConfig.bgpBestPathSelectionMode
    resource.routingConfig.bgpInterRegionCost
    resource.routingConfig.routingMode
    compute.googleapis.com/NetworkAttachment resource.connectionPreference
    resource.description
    resource.name
    resource.producerAcceptLists
    resource.producerRejectLists
    resource.subnetworks
    compute.googleapis.com/PacketMirroring resource.collectorIlb.url
    resource.description
    resource.enable
    resource.filter.cidrRanges
    resource.filter.direction
    resource.filter.IPProtocols
    resource.mirroredResources.instances.url
    resource.mirroredResources.subnetworks.url
    resource.mirroredResources.tags
    resource.name
    resource.network.url
    resource.priority
    compute.googleapis.com/Route resource.description
    resource.destRange
    resource.name
    resource.network
    resource.nextHopGateway
    resource.nextHopIlb
    resource.nextHopInstance
    resource.nextHopIp
    resource.nextHopVpnTunnel
    resource.priority
    resource.tags
    compute.googleapis.com/ServiceAttachment resource.connectionPreference
    resource.consumerAcceptLists.connectionLimit
    resource.consumerAcceptLists.networkUrl
    resource.consumerAcceptLists.projectIdOrNum
    resource.consumerRejectLists
    resource.description
    resource.domainNames
    resource.enableProxyProtocol
    resource.name
    resource.natSubnets
    resource.product.id
    resource.product.variantId
    resource.propagatedConnectionLimit
    resource.reconcileConnections
    resource.targetService
    compute.googleapis.com/Subnetwork resource.description
    resource.externalIpv6Prefix
    resource.internalIpv6Prefix
    resource.ipCidrRange
    resource.ipv6AccessType
    resource.logConfig.aggregationInterval
    resource.logConfig.enable
    resource.logConfig.filterExpr
    resource.logConfig.flowSampling
    resource.logConfig.metadata
    resource.logConfig.metadataFields
    resource.name
    resource.network
    resource.privateIpGoogleAccess
    resource.purpose
    resource.role
    resource.secondaryIpRanges.ipCidrRange
    resource.secondaryIpRanges.rangeName
    resource.stackType
    networkconnectivity.googleapis.com/InternalRange resource.allocationOptions.allocationStrategy
    resource.allocationOptions.firstAvailableRangesLookupSize
    resource.description
    resource.excludeCidrRanges
    resource.immutable
    resource.ipCidrRange
    resource.migration.source
    resource.migration.target
    resource.name
    resource.network
    resource.overlaps
    resource.peering
    resource.prefixLength
    resource.targetCidrRange
    resource.usage

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