Use 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:

  • secretmanager.googleapis.com/Secret

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 predefined 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.

Benefits

Use custom organization policies to do the following:

  • Enforce strict security requirements by mandating that users add annotations to secrets, set expiration dates on secrets, or set up delayed destruction of secret versions.
  • Support specific rotation requirements by requiring that all secrets within specific projects or folders set up rotation schedules.
  • Verify that annotations and version aliases match selected expressions in automated scripts.
  • Control cloud costs by restricting the types of secrets allowed within your organization.

Limitations

  • You can define a secret's expiration using either expire_time (a specific point in time) or ttl (a duration). In custom organization policies, you can only use expire_time to determine when the secret expires. If you set a ttl for a secret, Secret Manager converts it into an expire_time value for processing and evaluating the policy.

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.

    Go to project selector

  3. Make sure that billing is enabled for your Google Cloud project.

  4. Install the Google Cloud CLI.

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

    gcloud init

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

    Go to project selector

  7. Make sure that billing is enabled for your Google Cloud project.

  8. Install the Google Cloud CLI.

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

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

Required roles

To get the permissions that you need to manage organization policies, ask your administrator to grant you the following IAM roles:

For more information about granting roles, see Manage access to projects, folders, and organizations.

These predefined roles contain the permissions required to manage organization policies. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

The following permissions are required to manage organization policies:

  • orgpolicy.* on the organization resource
  • To create or update a Secret Manager secret:
    • secretmanager.secrets.create on the project resource
    • secretmanager.secrets.get on the project resource
    • secretmanager.secrets.list on the project resource
    • secretmanager.secrets.update on the project resource

You might also be able to get these permissions with custom roles or other predefined roles.

Create 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.

To create a custom constraint, create a YAML file using the following format:

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 you want for your new custom constraint. A custom constraint must start with custom., and can only include uppercase letters, lowercase letters, or numbers. For example, custom.ensureVersionDestroyTTL. The maximum length of this field is 70 characters.

  • RESOURCE_NAME: the fully qualified name of the Google Cloud resource containing the object and field you want to restrict. For example, secretmanager.googleapis.com/Secret.

  • CONDITION: a CEL condition that is written against a representation of a supported service resource. This field has a maximum length of 1000 characters. See Supported resources for more information about the resources available to write conditions against. For example, "resource.versionDestroyTtl < duration('30h')".

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

  • DISPLAY_NAME: a human-friendly name for the constraint. This field has a maximum length of 200 characters.

  • DESCRIPTION: a human-friendly description of the constraint to display as an error message when the policy is violated. This field has a maximum length of 2000 characters.

For more information about how to create a custom constraint, see Defining custom constraints.

Set up a custom constraint

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. Once completed, 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 boolean 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 for which you want to set the organization policy.
  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 enforcement of this organization policy is on or off.
  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. If this is a custom constraint, you can click Test changes to simulate the effect of this organization policy. For more information, see Test organization policy changes with Policy Simulator.
  10. To finish and apply the organization policy, click Set policy. The policy requires up to 15 minutes to take effect.

gcloud

To create an organization policy that enforces a boolean constraint, create a policy YAML file that references the constraint: 

      name: projects/PROJECT_ID/policies/CONSTRAINT_NAME
      spec:
        rules:
        - enforce: true

Replace the following:

  • PROJECT_ID: the project on which you want to enforce your constraint.
  • CONSTRAINT_NAME: the name you defined for your custom constraint. For example, custom.ensureVersionDestroyTTL.

To enforce the organization policy containing the constraint, run the following command: 

    gcloud org-policies set-policy POLICY_PATH

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 shows how to configure a custom constraint and policy to ensure that all new secrets created within a given project have a destruction delay duration (version_destroy_ttl) of at least 30 hours.

Before you begin, ensure the following:

Create the constraint

  1. Save the following file as constraint.yaml:

    name: organizations/ORGANIZATION_ID/customConstraints/custom.ensureVersionDestroyTTLAtLeast30hours
resourceTypes:
- secretmanager.googleapis.com/Secret
methodTypes:
- CREATE
condition: "resource.versionDestroyTtl < duration('30h')"
actionType: DENY
displayName: Enable Secret Version Destroy TTL with at least 30 hours
description: All new secrets must have Version Destroy TTL values of at least 30 hours

    This defines a constraint where for every new secret, if the secret version version_destroy_ttl is not applied or the version_destroy_ttl is less than 30 hours, the operation is denied.

  2. Apply the constraint:

    gcloud org-policies set-custom-constraint ~/constraint.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.ensureVersionDestroyTTLAtLeast30hours    DENY         CREATE         secretmanager.googleapis.com/Secret   Enable Secret Version Destroy TTL with at least 30 hours
...

Create the policy

  1. Save the following file as policy.yaml:

    name: projects/PROJECT_ID/policies/custom.ensureVersionDestroyTTLAtLeast30hours
spec:
  rules:
  - enforce: true

    Replace PROJECT_ID with your project ID.

  2. Apply the policy:

    gcloud org-policies set-policy ~/policy.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.ensureVersionDestroyTTLAtLeast30hours  -              SET               COCsm5QGENiXi2E=

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

Test the policy

gcloud secrets create org-policy-test-secret \
    --project=PROJECT_ID \
    --version-destroy-ttl=100000s

The output is the following:

Operation denied by custom org policies: ["customConstraints/custom.ensureVersionDestroyTTL": "All new secrets must have version destroy TTL values with at least 30 hours"]

Example custom organization policies for common use cases

The following table provides the syntax of some custom constraints for common use cases:

Description Constraint syntax
Must set version destroy TTL more than two days 
  name: organizations/ORGANIZATION_ID/customConstraints/custom.secretManagerEnableTTL
  resourceTypes:
  - secretmanager.googleapis.com/Secret
  methodTypes:
  - CREATE
  condition: "has(resource.versionDestroyTtl) && resource.versionDestroyTtl.getSeconds() > 172800"
  actionType: ALLOW
  displayName: Must set version destroy TTL more than one hour
  description: All new secrets must set version destroy TTL and version destroy TTL seconds should be more than two days
Set Pub/Sub topic 
  name: organizations/ORGANIZATION_ID/customConstraints/custom.secretsWithPubSubTopic
  resourceTypes:
  - secretmanager.googleapis.com/Secret
  methodTypes:
  - CREATE
  - UPDATE
  condition: "has(resource.topics) && size(resource.topics) > 0 && resource.topics[0].name.matches('projects/a_test_project/topics/a_topic_name')"
  actionType: ALLOW
  displayName: Set secret first topic as a_topic_name
  description: All secret must use a_topic_name Pub/Sub topic as the first topic for notifications.
Deny annotations with prefix 
    name: organizations/ORGANIZATION_ID/customConstraints/custom.secretManagerAnnotationPrefixes
    resourceTypes:
    - secretmanager.googleapis.com/Secret
    methodTypes:
    - CREATE
    condition: "has(resource.annotations) && resource.annotations['key1'].startsWith('some-prefix-')"
    actionType: DENY
    displayName: Deny annotation of 'key1' with prefix 'some-prefix-'
    description: All new secrets should not have 'key1' annotations set with prefix 'some-prefix-'.

Secret Manager supported resources

The table in this section lists the Secret Manager resources that you can reference in custom constraints.

To set resource locations constraints, use resource location organization policies. Similarly, to set constraints around CMEK usage, we recommend that you use CMEK organization policies.

Resource Field
secretmanager.googleapis.com/Secret resource.annotations
resource.expireTime
resource.rotation.nextRotationTime
resource.rotation.rotationPeriod
resource.topics.name
resource.versionAliases
resource.versionDestroyTtl

What's next