Setting up Binary Authorization for Anthos clusters on VMware

This document shows you how to set up Binary Authorization for Anthos clusters on VMware (GKE on-prem). It then shows you how to configure a sample Binary Authorization policy.

Before you begin

You must have Anthos clusters on VMware 1.4 or later installed and configured, with an admin and a user cluster. Your user cluster must be registered with Connect.
The Binary Authorization service uses a public IP address, accessible through a regular internet connection. Configure your Anthos clusters on VMware firewall rules for HTTPS to let the user cluster access the endpoint binaryauthorization.googleapis.com.
If you want to use centralized Cloud Audit Logs to view audit log entries, including those from Binary Authorization for Anthos clusters on VMware, you must configure Cloud Audit Logs in your user cluster configuration before you create the user cluster.
You must enable the Binary Authorization API as follows:
1. Go to Google Cloud Console.
  
  Enable APIs
2. In the project drop-down list, select your Connect project. You can find this Google Cloud project in the gkeConnect section of your user cluster configuration file. This is the Cloud project that connects your user cluster to Google Cloud.

Set up Binary Authorization for Anthos clusters on VMware

In this section, you set up Binary Authorization for Anthos clusters on VMware in your user cluster.

Specify installation environment variables

To specify the environment variables, do the following:

Use SSH to connect to your Anthos clusters on VMware admin workstation.
Specify your Connect project:
```
export PROJECT_ID=PROJECT_ID
```
Replace PROJECT_ID with the Cloud project in the gkeConnect section of your user cluster configuration file.
Specify the path of the user cluster's kubeconfig file:
```
export KUBECONFIG=PATH
```
Replace PATH with the path of your user cluster kubeconfig file.
Choose a name for the Binary Authorization API access service account:
```
export SA_NAME=SERVICE_ACCOUNT_NAME
```
Replace SERVICE_ACCOUNT_NAME with the service account name of your choice. The Binary Authorization Module uses this service account to access the Binary Authorization API.
Specify the path to the service account key file you download later in this guide:
```
export SA_JSON_PATH=SA_KEY_FILE_PATH
```
Replace SA_KEY_FILE_PATH with the path of the JSON key file for the service account.

Install the Binary Authorization Module in your user cluster

To install the Binary Authorization Module, do the following:

Set the default project for the gcloud command-line tool:
```
gcloud config set project ${PROJECT_ID}
```
Create a Binary Authorization API access service account:
```
gcloud iam service-accounts create ${SA_NAME}
```

Grant the binaryauthorization.policyEvaluator role to the Binary Authorization API access service account on your Connect project:

gcloud projects add-iam-policy-binding ${PROJECT_ID}\
  --member serviceAccount:${SA_NAME}@${PROJECT_ID}.iam.gserviceaccount.com\
  --role roles/binaryauthorization.policyEvaluator

Create a working directory:
1. Make a directory called binauthz.
2. Change to the directory.
Download the manifest.yaml file, which you use to install the Binary Authorization Module in your Anthos clusters on VMware user cluster:
```
gsutil cp gs://gke-on-prem-release/binauthz/manifest-0.2.1.yaml .
```

Create a YAML file for thebinauthz-system namespace.

Copy the following to a file called namespace.yaml:

apiVersion: v1
kind: Namespace
metadata:
  labels:
    control-plane: binauthz-controller
  name: binauthz-system

Create the namespace in your user cluster:
```
kubectl apply -f namespace.yaml
```
You see output similar to the following:
```
namespace/binauthz-system created
```

Download a JSON key file for your service account:

gcloud iam service-accounts keys create ${SA_JSON_PATH} --iam-account ${SA_NAME}@${PROJECT_ID}.iam.gserviceaccount.com

Save the service account key as a Kubernetes Secret in your user cluster:

kubectl --namespace binauthz-system create secret generic binauthz-sa --from-file=key.json=${SA_JSON_PATH}

Install the Binary Authorization Module in your user cluster:
```
kubectl apply -f manifest-0.2.1.yaml
```
Verify the Deployment was created:
```
kubectl get pod --namespace binauthz-system
```
You see the Pod binauthz-module-deployment-* listed with Status of Running and 1/1 Pods ready, similar to this output:

NAME                                          READY   STATUS    RESTARTS   AGE
binauthz-module-deployment-5fddf9594f-qjprz   1/1     Running   0          11s

Use Binary Authorization for Anthos clusters on VMware

This section shows you how to set up and use Binary Authorization policies.

In each example, you configure the policy and then test it by attempting to deploy a container image in your Anthos clusters on VMware user cluster.

Allow all

This section demonstrates a success case. You configure the Binary Authorization policy so that a container image satisfies the policy and is deployed.

In Google Cloud, do the following:

Google Cloud Console

In the Google Cloud Console, go to the Binary Authorization page.

Go to Binary Authorization

Make sure to select your Connect project ID.
Click Edit Policy.
Under Project default rule, select Allow all images.
Click Save policy.

command-line

Set the PROJECT_ID for your Connect project. You can find this project ID in the gkeConnect field in your user cluster configuration file.
```
export PROJECT_ID=PROJECT_ID
```
Set the default Google Cloud project.
```
gcloud config set project ${PROJECT_ID}
```

Export the policy YAML file to your local system:

gcloud container binauthz policy export  > policy.yaml

Your YAML file looks like the following:

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/<var>PROJECT_ID</var>/policy

Edit policy.yaml.
Set evaluationMode to ALWAYS_ALLOW.
If you have a requireAttestationsBy block in the file, delete this block.
Save the file.

Import policy.yaml as follows:

gcloud container binauthz policy import policy.yaml

On your Anthos clusters on VMware admin workstation, do the following:

Create a manifest file for a Pod.

Save the following to a file called pod.yaml:

apiVersion: v1
kind: Pod
metadata:
  name: test-pod
spec:
  containers:
  - name: test-container
    image: gcr.io/google-samples/hello-app@sha256:c62ead5b8c15c231f9e786250b07909daf6c266d0fcddd93fea882eb722c3be4

Create the Pod:
```
kubectl apply -f pod.yaml
```
You see that the Pod was successfully deployed.
Delete the Pod:
```
kubectl delete -f pod.yaml
```

Disallow all

This section demonstrates a failure case. In this section, you configure the default policy to disallow your container image from being deployed.

In Google Cloud do the following:

Google Cloud Console

In the Google Cloud Console, go to the Binary Authorization page.

Go to Binary Authorization

Make sure your Connect project is selected.
Click Edit Policy.
Under Project default rule, select Disallow all images.
Click Save policy.

command-line

Set the PROJECT_ID to your Connect project ID.
```
export PROJECT_ID=PROJECT_ID
```

Set the default Cloud project.

gcloud config set project ${PROJECT_ID}

Export the policy YAML file:

gcloud container binauthz policy export  > policy.yaml

Edit policy.yaml.
Set evaluationMode to ALWAYS_DENY.
If you have a requireAttestationsBy block in the file, delete this block.
Save the file.

Import policy.yaml as follows:

gcloud container binauthz policy import policy.yaml

On your Anthos clusters on VMware admin workstation, do the following:

Create a manifest file for a Pod.

Save the following to a file called pod.yaml:

apiVersion: v1
kind: Pod
metadata:
  name: test-pod
spec:
  containers:
  - name: test-container
    image: gcr.io/google-samples/hello-app@sha256:c62ead5b8c15c231f9e786250b07909daf6c266d0fcddd93fea882eb722c3be4

Create the Pod:
```
kubectl apply -f pod.yaml
```

You see that the Pod was was blocked from being deployed. The output looks like the following:

Error from server (VIOLATES_POLICY): error when creating "pod.yaml": admission webhook "binaryauthorization.googleapis.com" denied the request: Denied by default admission rule. Overridden by evaluation mode

Get the user cluster resource ID

This section shows you how to compose the cluster resource ID for your user cluster. In your Binary Authorization policy, you can create cluster-specific rules. You associate these rules with a cluster-specific resource ID, which is based on your cluster ID.

You get the resource ID as follows:

Google Cloud Console

In the Cloud Console, go to the Anthos Clusters page.

Go to Clusters
Select the Connect project ID for Anthos clusters on VMware. You can find this project ID in the gkeConnect section of your user cluster configuration file.
Under Anthos Managed Clusters, find your cluster ID under the Name column.
To create the resource ID, add the prefix global. to the cluster ID so that the resource ID has the following format: global.CLUSTER_ID.

command-line tool

Use SSH to connect to your Anthos clusters on VMware admin workstation.
On the admin workstation, run the following command:
```
kubectl get membership -o yaml
```

Get the cluster ID from spec.owner.id field of the output. Example output follows:

apiVersion: v1
items:
- apiVersion: hub.gke.io/v1
  kind: Membership
  ...
  spec:
    owner:
      id: //gkehub.googleapis.com/projects/PROJECT_NUMBER/locations/global/memberships/my-cluster-id

In the example output, the cluster ID is my-cluster-id.

To create the resource ID, add the prefix global. to the cluster ID. In the example, the resource ID is global.my-cluster-id.

You use this resource ID when you define cluster-specific rules. Learn how to set cluster-specific rules using the Google Cloud Console or using a command-line tool.

Clean up

The following code sample shows how to disable the webhook:

kubectl delete ValidatingWebhookConfiguration/binauthz-validating-webhook-configuration

The following code sample shows how to re-enable the webhook:
```
kubectl apply -f manifest-0.2.1.yaml
```
The following code sample shows how to delete all of the resources related to Binary Authorization:
```
kubectl delete -f manifest-0.2.1.yaml
kubectl delete namespace binauthz-system
```

What's next

See Enabling dry run to check policy compliance at Pod creation time without actually blocking the Pod from being created.
See Using breakglass to force a Pod to be created that the Binary Authorization enforcer would otherwise block.
To implement an attestor-based Binary Authorization policy, see:
- Configuring a policy using the Google Cloud Console or a command-line tool . Set the default or cluster-specific rule to require attestations.
- Create an attestor using the Google Cloud Console or a command-line tool .
- Create an attestation.
To see log events related to Binary Authorization for Anthos clusters on VMware, see Viewing Cloud Audit Logs events.
Monitoring metrics.