Creating and managing custom constraints

This page shows you how to use Organization Policy Service custom constraints to restrict specific operations on the following Cloud de Confiance by S3NS resources:

  • apikeys.googleapis.com/Key

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

About organization policies and constraints

The Cloud de Confiance 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 Cloud de Confiance resources and descendants of those resources in the Cloud de Confiance by S3NS resource hierarchy. You can enforce organization policies at the organization, folder, or project level.

Organization Policy provides built-in managed constraints for various Cloud de Confiance 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, Cloud de Confiance 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.

Benefits

  • Cost management: use organization policies to restrict the VM instance and disk sizes and types that can be used in your organization. You can also restrict the machine family that is used for the VM instance.
  • Security, compliance, and governance: you can use custom organization policies as follows:
    • To enforce security requirements, you can require specific firewall port rules on VMs.
    • To support hardware isolation or licensing compliance, you can require all VMs within a specific project or folder to run on sole-tenant nodes.
    • To govern automation scripts, you can use custom organization policies to verify that labels match desired expressions.

Before you begin

  1. In the Cloud de Confiance console, on the project selector page, select or create a Cloud de Confiance 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

  2. Verify that billing is enabled for your Cloud de Confiance project.

  3. Install the Google Cloud CLI.

  4. Configure the gcloud CLI to use your federated identity.

    For more information, see Sign in to the gcloud CLI with your federated identity.

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

    gcloud init
  6. 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 Cloud de Confiance 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 Cloud de Confiance 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 Cloud de Confiance by S3NS services support both methods. To see supported methods for each service, find the service in Supported services.

  10. 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.
  11. Under Action, select whether to allow or deny the evaluated method if the condition is met.
  12. 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.

  13. Click Create constraint.
  14. 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.allowOnlyStartsWithKeyName. This field can contain up to 70 characters.
    • RESOURCE_NAME: the fully qualified name of the Cloud de Confiance resource containing the object and field that you want to restrict. For example, apikeys.googleapis.com/Key.
    • 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.displayName.startsWith('key-')".
    • For more information about the resources available to write conditions against, see Supported resources.

    • ACTION: the action to take if the condition is met. Possible values are ALLOW and DENY.
    • 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.

      The deny action means that if the condition evaluates to true, the operation to create or update the resource 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.
  3. 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:
  4.         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 Cloud de Confiance by S3NS organization policies.

  5. To verify that the custom constraint exists, use the gcloud org-policies list-custom-constraints command:
  6.       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 Cloud de Confiance by S3NS resource.

Console

  1. In the Cloud de Confiance 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.allowOnlyStartsWithKeyName.
  3. To enforce the organization policy in dry-run mode, run the following command with the dryRunSpec flag:
  4.         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.

  5. 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:
  6.         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 and policy that requires the display name of all new API Keys in a specific project should start with the key-.

Before you begin, you need to know the following:

  • Your organization ID
  • A project ID

Create the constraint

  1. Save the following file as constraint-allow-only-starts-with-key.yaml:

    name: organizations/ORGANIZATION_ID/customConstraints/custom.allowOnlyStartsWithKeyName
    resourceTypes:
    - apikeys.googleapis.com/Key
    methodTypes:
    - CREATE
    condition: "resource.displayName.startsWith('key-')"
    actionType: ALLOW
    displayName: Only new API Keys with the display name starting with 'key-' are allowed.
    description: Restrict all other key creation with the display name starting with 'key-'.
    

    This defines a constraint where for every new API Key, if the display name is not starting with key-, the operation is denied.

  2. Apply the constraint:

    gcloud org-policies set-custom-constraint ~/constraint-allow-only-starts-with-key.yaml
    
  3. Verify that the constraint exists:

    gcloud org-policies list-custom-constraints --organization=ORGANIZATION_ID
    

    The output is similar to the following:

    CUSTOM_CONSTRAINT                       ACTION_TYPE  METHOD_TYPES   RESOURCE_TYPES                     DISPLAY_NAME
    custom.allowOnlyStartsWithKeyName       ALLOW        CREATE         apikeys.googleapis.com/Key         Only new API Keys with the display name starting with 'key-' are allowed.
    ...
    

Create the policy

  1. Save the following file as policy-allow-only-starts-with-key.yaml:

    name: projects/PROJECT_ID/policies/custom.allowOnlyStartsWithKeyName
    spec:
      rules:
      - enforce: true
    

    Replace PROJECT_ID with your project ID.

  2. Apply the policy:

    gcloud org-policies set-policy ~/policy-allow-only-starts-with-key.yaml
    
  3. Verify that the policy exists:

    gcloud org-policies list --project=PROJECT_ID
    

    The output is similar to the following:

    CONSTRAINT                        LIST_POLICY    BOOLEAN_POLICY    ETAG
    custom.allowOnlyStartsWithKeyName -              SET               COCsm5QGENiXi2E=
    

After you apply the policy, wait for about two minutes for Cloud de Confiance to start enforcing the policy.

Test the policy

Try to create a new API Key with the display name not-key in the project:

gcloud services api-keys create --display-name=not-key

The output is the following:

Operation denied by org policy: ["customConstraints/custom.allowOnlyStartsWithKeyName": "Only new API Keys with the display name starting with 'key-' are allowed."]

Example custom organization policies for common use cases

This table provides syntax examples for some common custom constraints.

Description Constraint syntax
Only new API Keys with the display name starting with 'key-' are allowed.
    name: organizations/ORGANIZATION_ID/customConstraints/custom.allowOnlyStartsWithKeyName
    resourceTypes:
    - apikeys.googleapis.com/Key
    methodTypes:
    - CREATE
    condition: "resource.displayName.startsWith('key-')"
    actionType: ALLOW
    displayName: Only new API Keys with the display name starting with 'key-' are allowed.
    description: Restrict all other key creation with the display name starting with 'key-'.
    
Only API Keys bound to 'test-sa@test-project.iam.gserviceaccount.com' are allowed to be created/updated.
    name: organizations/ORGANIZATION_ID/customConstraints/custom.denyTestServiceAccountBound
    resourceTypes:
    - apikeys.googleapis.com/Key
    methodTypes:
    - CREATE
    - UPDATE
    condition: "resource.serviceAccountEmail != 'test-sa@test-project.iam.gserviceaccount.com'"
    actionType: ALLOW
    displayName: Only API Keys bound to 'test-sa@test-project.iam.gserviceaccount.com' are allowed.
    description: Restrict all other key creation or update to only be bound to the test service account 'test-sa@test-project.iam.gserviceaccount.com'.
    
Only new API Keys with the IP '1.1.1.1' in the allowlist can be created.
    name: organizations/ORGANIZATION_ID/customConstraints/custom.allowOnlyIP1111
    resourceTypes:
    - apikeys.googleapis.com/Key
    methodTypes:
    - CREATE
    condition: "'1.1.1.1' in resource.restrictions.serverKeyRestrictions.allowedIps"
    actionType: ALLOW
    displayName: Only new API Keys with the IP '1.1.1.1' in the allowlist can be created.
    description: Restrict all other key creation with the IP '1.1.1.1' in the allowlist.
    
Deny API Keys update targeting the myservice.googleapis.com service.
    name: organizations/ORGANIZATION_ID/customConstraints/custom.denyUpdateMyService
    resourceTypes:
    - apikeys.googleapis.com/Key
    methodTypes:
    - UPDATE
    condition: "resource.restrictions.apiTargets.exists(target, target.service == 'myservice.googleapis.com')"
    actionType: DENY
    displayName: Deny API Keys update targeting the myservice.googleapis.com service.
    description: Block myservice.googleapis.com service API Keys update.
    

API Keys supported resources

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

Resource Field
apikeys.googleapis.com/Key resource.displayName
resource.restrictions.androidKeyRestrictions.allowedApplications.packageName
resource.restrictions.androidKeyRestrictions.allowedApplications.sha1Fingerprint
resource.restrictions.apiTargets.methods
resource.restrictions.apiTargets.service
resource.restrictions.browserKeyRestrictions.allowedReferrers
resource.restrictions.iosKeyRestrictions.allowedBundleIds
resource.restrictions.serverKeyRestrictions.allowedIps
resource.serviceAccountEmail

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