Quickstart: Allow all and disallow all

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The terms: whitelist

This quickstart shows how to configure and test a basic rule in a Binary Authorization policy.

In this quickstart, you view and configure the default rule in the policy. The default rule allows all images to be deployed. You test this by deploying a container image on a Google Kubernetes Engine (GKE) cluster. You then set the default rule to disallow all images from being deployed and attempt to deploy an image.

Note: This is not a real-world policy. A typical policy requires an attestation to accompany the image before the Binary Authorization enforcer allows the image to be deployed. For an end-to-end tutorial about attestations, see Getting started using the CLI or Getting started using the Console.

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 Cloud project. Learn how to confirm that billing is enabled for your project.

4. Enable the Artifact Registry, Binary Authorization APIs.

   Enable the APIs

5. Install and initialize the Cloud SDK.
6. Install kubectl.

Note: It can take a few minutes for this operation to complete.

Create a cluster with Binary Authorization enabled

Now, 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 Cloud Console.

   Go to the GKE page

   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 the Enable Binary Authorization checkbox.

   

8. Click Create.

Note: Creating a cluster can take several minutes.

gcloud

Run gcloud container clusters create with the --enable-binauthz flag enabled.

gcloud container clusters create \
    --enable-binauthz \
    --zone us-central1-a \
    test-cluster

Default policy

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

Cloud Console

To view the default policy:

1. Go to the Binary Authorization page in the Cloud Console.

   Go to the Binary Authorization page

   The console displays details about the policy.

   

2. Click Configure Policy or, if a policy exists, 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:

gcloud container binauthz policy export

By default, the file has the following contents:

admissionWhitelistPatterns:
- namePattern: gcr.io/google_containers/*
- namePattern: gcr.io/google-containers/*
- namePattern: k8s.gcr.io/*
- namePattern: gke.gcr.io/*
- namePattern: gcr.io/stackdriver-agents/*
globalPolicyEvaluationMode: ENABLE
defaultAdmissionRule:
  evaluationMode: ALWAYS_ALLOW
  enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
name: projects/PROJECT_ID/policy

Note: we no longer recommend using admissionWhitelistPatterns to allowlist Google-managed system images as shown above. To allowlist Google-managed system images, globalPolicyEvaluationMode should be set to ENABLE. See globalPolicyEvaluationMode for details.

REST API

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

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",
  "admissionWhitelistPatterns": [
    {
      "namePattern": "gcr.io/google_containers/*"
    },
    {
      "namePattern": "gcr.io/google-containers/*"
    },
    {
      "namePattern": "k8s.gcr.io/*"
    },
    {
      "namePattern": "gke.gcr.io/*"
    },
    {
      "namePattern": "gcr.io/stackdriver-agents/*"
    }
  ],
  "globalPolicyEvaluationMode": "ENABLE",
  "defaultAdmissionRule": {
    "evaluationMode": "ALWAYS_ALLOW",
    "enforcementMode": "ENFORCED_BLOCK_AND_AUDIT_LOG"
  }
}

Note: we no longer recommend using admissionWhitelistPatterns to allowlist Google-managed system images as shown above. To allowlist Google-managed system images, globalPolicyEvaluationMode should be set to ENABLE. See globalPolicyEvaluationMode for details.

Test the policy

You can test the policy by trying to deploy a sample container image to the cluster.

For this quickstart, you use the sample container image located at the path gcr.io/google-samples/hello-app in Container Registry. This is a public container image created by Google that contains a "Hello, World!" sample application.

Cloud Console

To test the policy:

1. Go to the GKE Clusters page in the Cloud Console.

   Go to the GKE page

2. Click Deploy.

   The console prompts you to enter details about the deployment.

3. Select Existing Container Image.

   

4. Enter gcr.io/google-samples/hello-app:1.0 as the container image path.

5. Click Continue.

   

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

7. Click Deploy.

kubectl

To test the policy:

1. Update the local kubeconfig file:

   gcloud container clusters get-credentials \
       --zone us-central1-a \
       test-cluster
   

   This provides the credentials and endpoint information required to access the cluster in GKE.

2. Deploy the image:

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

Now, verify that the deployment was allowed by Binary Authorization.

Cloud Console

To verify that the image was deployed, go to the GKE Workloads page in Cloud Console.

Go to the GKE page

A workload for the deployment appears with a green icon that indicates that the image was deployed successfully.

kubectl

To verify that the image was deployed:

kubectl get pods

The command prints a message similar to the following, which indicates that deployment was successful:

NAME                            READY     STATUS    RESTARTS   AGE
hello-server-579859fb5b-h2k8s   1/1       Running   0          1m

Make sure to delete the deployment so you can continue to the next step:

Cloud Console

To delete the deployment:

1. Return to the GKE Workloads page in Cloud Console.

   Go to the GKE page

2. Select the test-server workload.

3. Click Delete.

kubectl

To delete the deployment:

kubectl delete deployment hello-server

Configure the policy to disallow all images

Now, modify the policy to block instead of allow all images to be deployed.

Cloud Console

To modify the policy:

1. Return to the Binary Authorization page in the Cloud Console.

   Go to the Binary Authorization page

2. Click Edit Policy.

3. Select Disallow All Images.

   

4. Click Save Policy.

gcloud

To modify the policy:

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.

   The policy YAML file should appear as follows:

   globalPolicyEvaluationMode: ENABLE
   defaultAdmissionRule:
     evaluationMode: ALWAYS_DENY
     enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
   name: projects/PROJECT_ID/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:

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

   cat > /tmp/policy.json << EOM
   {
     "name": "projects/${PROJECT_ID}/policy",
     "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"
   

Retest the policy

Again, test the policy by deploying a sample container image to the cluster. This time, Binary Authorization blocks the image from being deployed.

Cloud Console

Deploy the image:

1. Go to the GKE Clusters page in the Cloud Console.

   Go to the GKE page

2. Click Deploy.

   The console prompts you to enter details about the deployment.

3. Select Existing Container Image.

   

4. Enter gcr.io/google-samples/hello-app:1.0 as the container image path.

5. Click Continue.

   

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

7. Click Deploy.

kubectl

Deploy the image:

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

You can now verify that the policy was blocked:

Cloud Console

To verify that the image was not deployed:

Return to the GKE Workloads page in Cloud Console.

Go to the GKE page

A workload for the container image appears with a red icon that indicates that the image failed to be deployed.

kubectl

To verify that the image was not deployed:

kubectl get pods

The command prints the following message, which indicates that the image was not deployed:

No resources found.

You can get further details about the deployment:

kubectl get event --template \
'{{range.items}}{{"\033[0;36m"}}{{.reason}}:{{"\033[0m"}}{{.message}}{{"\n"}}{{end}}'

which shows that the deployment was disallowed by the policy:

FailedCreate:Error creating: pods "hello-server-579859fb5b-lvfgd" is forbidden:
image policy webhook backend denied one or more images: Denied by default admission
rule. Overridden by evaluation mode

Clean up

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

Delete the cluster you created in GKE:

Cloud Console

To delete the cluster:

1. Go to the GKE Clusters page in the Cloud Console.

   Go to the GKE page

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

gcloud

To delete the cluster:

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

What's next

• Learn how to set up and enforce a policy with required attestations. See:
  • Getting started using the CLI
  • Getting started using Cloud Console
• Read our resources about DevOps and explore our research program.