Update a Binary Authorization policy

Update a Binary Authorization policy

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The terms: whitelist

This document describes how to exempt images in Binary Authorization policies.

In this document, you update the policy to exempt container images in Container Registry and Artifact Registry from Binary Authorization enforcement and set the default rule to disallow all other containers from being deployed.

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.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

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

4. Enable the Artifact Registry, Binary Authorization APIs.

   Enable the APIs

5. Install the Google Cloud CLI.

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.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

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

9. Enable the Artifact Registry, Binary Authorization APIs.

   Enable the APIs

10. Install the Google Cloud CLI.

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

    gcloud init

12. If you are not using Cloud Shell, install kubectl.

Create a cluster with Binary Authorization enabled

Create a GKE cluster with Binary Authorization enabled. This is the cluster where you want your deployed container images to run.

Google Cloud console

1. Go to the GKE Clusters page in the Google Cloud console.

   Go to GKE

   The console displays a list of GKE clusters in your Google Cloud project.

2. Click Create Cluster.

3. Enter test-cluster in the Name field.

   

4. Select Zonal in the Location Type options.

5. Select us-central1-a from the Zone drop-down list.

6. Click the Security link to reveal the Security panel.

7. In the Security panel, select Enable Binary Authorization.

   

8. Select Enforce-only.

9. Click Create.

Note: Creating a cluster can take several minutes.

gcloud

Run gcloud container clusters create with the --binauthz-evaluation-mode=PROJECT_SINGLETON_POLICY_ENFORCE flag enabled.

gcloud container clusters create \
    --binauthz-evaluation-mode=PROJECT_SINGLETON_POLICY_ENFORCE \
    --zone us-central1-a \
    test-cluster

View the Default policy

By default, your Binary Authorization policy is configured to allow all container images to be deployed.

Google Cloud console

To view the default policy, do the following:

1. Go to the Binary Authorization page in the Google Cloud console.

   Go to Binary Authorization

   The console displays details about the policy.

2. Click Edit Policy.

3. In Project Default Rule, the option Allow All Images is selected.

gcloud

To view the default policy, export the policy YAML file, do the following:

gcloud container binauthz policy export

By default, the file has the following contents:

globalPolicyEvaluationMode: ENABLE
defaultAdmissionRule:
  evaluationMode: ALWAYS_ALLOW
  enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
name: projects/<var>PROJECT_ID</var>/policy

REST API

To view the default policy, retrieve it in JSON format as follows:

curl \
    -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
    -H "x-goog-user-project: ${PROJECT_ID}" \
    "https://binaryauthorization.googleapis.com/v1/projects/${PROJECT_ID}/policy"

The REST API returns the following:

{
  "name": "projects/PROJECT_ID/policy",
  "globalPolicyEvaluationMode": "ENABLE",
  "defaultAdmissionRule": {
    "evaluationMode": "ALWAYS_ALLOW",
    "enforcementMode": "ENFORCED_BLOCK_AND_AUDIT_LOG"
  }
}

Allow only exempt images

This section describes how to modify the policy to exempt images and disallow all other images from being deployed.

Google Cloud console

To modify the policy, do the following:

1. Return to the Binary Authorization page in the Google Cloud console.

   Go to Binary Authorization

2. Click Edit Policy.

3. Select Disallow All Images.

4. Under Images exempt from deployment rules, expand Image paths.

5. Click Add Image Paths.

   Container Registry

   In New image path, paste the following path from an Container Registry repository:

   gcr.io/google-samples/hello-app:1.0
   

   Artifact Registry

   In New image path, paste the following path from an Artifact Registry repository:

   us-docker.pkg.dev/google-samples/containers/gke/hello-app:1.0
   

6. Click Done to save the image path.

7. Click Save Policy.

gcloud

To modify the policy to allow example images from Container Registry and Artifact Registry, do the following:

1. Export the policy YAML file:

   gcloud container binauthz policy export  > /tmp/policy.yaml
   

2. In a text editor, change the evaluationMode from ALWAYS_ALLOW to ALWAYS_DENY and add exempt images to admissionWhitelistPatterns.

   To exempt the following example images from Container Registry and Artifact Registry, modify your policy YAML file as follows:

   admissionWhitelistPatterns:
   - namePattern: gcr.io/google-samples/hello-app:1.0
   - namePattern: us-docker.pkg.dev/google-samples/containers/gke/hello-app:1.0
   globalPolicyEvaluationMode: ENABLE
   defaultAdmissionRule:
     evaluationMode: ALWAYS_DENY
     enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
   name: projects/<var>PROJECT_ID</var>/policy
   

3. Import the policy YAML file back into Binary Authorization:

   gcloud container binauthz policy import /tmp/policy.yaml
   

REST API

To modify the policy, do the following:

1. Create a text file with the updated policy in JSON format:

   cat > /tmp/policy.json << EOM
   {
     "name": "projects/${PROJECT_ID}/policy",
     "admissionWhitelistPatterns": [
       {
         "namePattern": "gcr.io/google-samples/hello-app:1.0"
       },
       {
         "namePattern": "us-docker.pkg.dev/google-samples/containers/gke/hello-app:1.0"
       }
     ],
     "globalPolicyEvaluationMode": "ENABLE",
     "defaultAdmissionRule": {
       "evaluationMode": "ALWAYS_DENY",
       "enforcementMode": "ENFORCED_BLOCK_AND_AUDIT_LOG"
     }
   }
   EOM
   

2. Send the updated policy to the REST API:

   curl -X PUT \
       -H "Content-Type: application/json" \
       -H "Authorization: Bearer $(gcloud auth application-default print-access-token)" \
       -H "x-goog-user-project: ${PROJECT_ID}" \
       --data-binary @/tmp/policy.json  \
       "https://binaryauthorization.googleapis.com/v1/projects/${PROJECT_ID}/policy"
   

Test the policy

To test the policy by deploying image you added to the Exempt image allowlist, do the following:

1. Deploy an exempt image to the cluster.

   Google Cloud console

   Deploy an exempt image:

   1. Go to the GKE Clusters page in the Google Cloud console.

      Go to GKE

   2. Click Deploy.

      The console prompts you to enter details about the deployment.

   3. Select Existing Container Image.

   4. Enter the container image path.

      Container Registry

      To deploy an image from Container Registry enter the following:

      gcr.io/google-samples/hello-app:1.0
      

      Artifact Registry

      To deploy an image from Artifact Registry enter the following:

      us-docker.pkg.dev/google-samples/containers/gke/hello-app:1.0
      

   5. Click Continue.

   6. Enter hello-server in the Application Name field.

   7. Click Deploy.

   kubectl

   Container Registry

   Deploy the image from Container Registry:

   kubectl run hello-server --image gcr.io/google-samples/hello-app:1.0 --port 8080
   

   Artifact Registry

   Deploy the image from Artifact Registry:

   kubectl run hello-server --image us-docker.pkg.dev/google-samples/containers/gke/hello-app:1.0 --port 8080
   

2. Verify that the image was allowed to deploy:

   Google Cloud console

   To verify that the image was deployed, do the following:

   1. Go to the GKE page.

   Go to GKE

   1. Go to the Workloads page.

   The hello-server workload appears with a green icon, indicating it is running.

   kubectl

   To verify that the image was allowed to deploy, enter the following command:

   kubectl get pods
   

   You see the image running.

3. Delete the pod.

   Google Cloud console

   In the GKE Workloads page:

   1. Select the hello-server workload.

   2. Click Delete.

   3. When prompted to delete resources, click Delete.

   kubectl

   kubectl delete pod hello-server
   

Clean up

To avoid incurring charges to your Google Cloud account for the resources used on this page, follow these steps.

Delete the cluster you created in GKE:

Console

To delete the cluster, do the following:

1. Go to the GKE Clusters page in the Google Cloud console.

   Go to GKE

2. Select the test-cluster cluster and click Delete.

gcloud

To delete the cluster, enter the following command:

gcloud container clusters delete \
    --zone=us-central1-a \
    test-cluster

What's next

• To learn more about exempting images, including using wildcards to exempt multiple images, see Exempt images.
• For end-to-end tutorials that describe how to set up and enforce a policy that requires attestations, see the following:
  • Get started using the Google Cloud CLI
  • Get started using the Google Cloud console
• Read our resources about DevOps and explore the DevOps Research and Assessment (DORA) research program.