Configure a multi-project setup

Set up the deployer project

The deployer project manages the Google Kubernetes Engine (GKE) clusters, where you deploy images, and the Binary Authorization policy that Binary Authorization enforces at deploy time. You can have more than one deployer project, depending on the size, complexity, and other requirements of your environment.

To set up the deployer project:

1. Create the project and enable billing in Google Cloud console if you have not already done so.

2. Identity and Access Management note: The deployer project contains your GKE cluster. The Identity and Access Management configuration for this project should reflect that.

3. Set environment variables to store the Google Cloud project and number:

   DEPLOYER_PROJECT_ID=DEPLOYER_PROJECT_ID
   

   Replace DEPLOYER_PROJECT_ID with the Google Cloud project ID.

   DEPLOYER_PROJECT_NUMBER=$(gcloud projects describe "${DEPLOYER_PROJECT_ID}" \
       --format="value(projectNumber)")
   

4. Enable APIs:

   Artifact Registry

   gcloud --project=${DEPLOYER_PROJECT_ID} \
     services enable\
     container.googleapis.com\
     artifactregistry.googleapis.com\
     binaryauthorization.googleapis.com
   

5. Get the deployer project service account name:

   DEPLOYER_SERVICE_ACCOUNT="service-${DEPLOYER_PROJECT_NUMBER}@gcp-sa-binaryauthorization.iam.gserviceaccount.com"
   

   You use the service account name in a later step when you configure permissions on the Artifact Analysis note associated with your attestor.

Set up the attestor project

An attestor project stores the attestors that can verify that an image is ready for deployment. Often, you have a single attestor project that acts as a centralized store for information about trusted parties in the authorization process. This allows you to centrally manage security keys required to verify the identity of attestors and to restrict access to only those parties who administer them.

To set up the attestor project:

1. Create the project and enable billing in Google Cloud console if you have not already done so.

2. Identity and Access Management note: Because the this project contains your attestors, only security personnel should have write access.

3. Set environment variables to store the project ID and number:

   ATTESTOR_PROJECT_ID=ATTESTOR_PROJECT_ID
   

   Replace ATTESTOR_PROJECT_ID with the attestor project ID.

   ATTESTOR_PROJECT_NUMBER=$(gcloud projects describe "${ATTESTOR_PROJECT_ID}" \
       --format="value(projectNumber)")
   

4. Enable the Artifact Analysis and Binary Authorization APIs:

   gcloud services --project=${ATTESTOR_PROJECT_ID} \
       enable containeranalysis.googleapis.com \
       binaryauthorization.googleapis.com
   

5. Get the attestor project service account name:

   ATTESTOR_SERVICE_ACCOUNT="service-${ATTESTOR_PROJECT_NUMBER}@gcp-sa-binaryauthorization.iam.gserviceaccount.com"
   

   You use the service account name in a later step when you configure permissions on the Artifact Analysis note associated with your attestor.

Set up the attestations project

An attestation project is one that stores attestations that attestors make when they verify an image. A separate attestation project allows you to organize and inspect statements about software readiness more easily.

1. Create the project and enable billing in Google Cloud console if you have not already done so.

2. Identity and Access Management note: All roles involved in binary authorization should have read access to the Artifact Analysis Notes and Occurrences in this project, however only attestation managers need to have write access.

3. Set an environment variable to store the project name:

   ATTESTATION_PROJECT_ID=ATTESTATION_PROJECT_ID
   

   Replace ATTESTATION_PROJECT_ID with the attestation project ID.

4. Enable the Artifact Analysis and Binary Authorization APIs:

   gcloud services --project=${ATTESTATION_PROJECT_ID} \
       enable containeranalysis.googleapis.com \
       binaryauthorization.googleapis.com
   

Create a cluster

Now you can create a GKE cluster in the deployer project. This is the cluster where you want your deployed container images to run. When you create the cluster, you pass the --binauthz-evaluation-mode=PROJECT_SINGLETON_POLICY_ENFORCE flag to the gcloud container clusters create command.

To create the cluster:

gcloud --project=${DEPLOYER_PROJECT_ID} \
    container clusters create \
    --binauthz-evaluation-mode=PROJECT_SINGLETON_POLICY_ENFORCE \
    --zone us-central1-a \
    test-cluster

Here, you create a cluster named test-cluster in the GKE zone us-central1-a.

You must also update the local kubeconfig file for your kubectl installation. This provides the credentials and endpoint information required to access the cluster in GKE.

To update the local kubeconfig file:

gcloud --project=${DEPLOYER_PROJECT_ID} \
    container clusters get-credentials \
    --zone us-central1-a \
    test-cluster

Create an attestor

An attestor is a party that is responsible for attesting that a required process has completed before a container image can be deployed. This party can be a human user or, more often, a machine process like a build and test system, or your continuous integration (CI) and deployment (CD) pipelines. You create attestors in your attestor project.

Creating an attestor requires you to:

• Create a note in Artifact Analysis to store trusted metadata used in the authorization process
• Create the attestor itself in the attestor project and associate the note you created
• Add an IAM role binding for the deployer project service account to the attestor
• Set permissions on the Artifact Analysis note

For this tutorial, you have one attestor named test-attestor and a Container Analysis note named test-attestor-note. In a real-world scenario, you can have any number of attestors, each one representing a party that participates in the authorization process for the image.

Create the Artifact Analysis note

1. Set variables that store the name of your attestor and Artifact Analysis note:

   ATTESTOR_NAME=test-attestor
   NOTE_ID=test-attestor-note
   

   Replace:

   • test-attestor: attestor name of your choice.
   • test-attestor-note: attestor note name of your choice.

2. Create a JSON file in /tmp/note_payload.json that describes the Container Analysis note:

   cat > /tmp/note_payload.json << EOM
   {
     "name": "projects/${ATTESTOR_PROJECT_ID}/notes/${NOTE_ID}",
     "attestation": {
       "hint": {
         "human_readable_name": "Attestor Note"
       }
     }
   }
   EOM
   

3. Create the note by sending an HTTP request to the Artifact Analysis REST API:

   curl -X POST \
       -H "Content-Type: application/json" \
       -H "Authorization: Bearer $(gcloud auth print-access-token)"  \
       --data-binary @/tmp/note_payload.json  \
       "https://containeranalysis.googleapis.com/v1/projects/${ATTESTOR_PROJECT_ID}/notes/?noteId=${NOTE_ID}"
   

4. Verify that the note was created:

   curl \
   -H "Authorization: Bearer $(gcloud auth print-access-token)" \
   "https://containeranalysis.googleapis.com/v1/projects/${ATTESTOR_PROJECT_ID}/notes/${NOTE_ID}"
   

Create the attestor

Now, you can create the attestor:

1. Create the attestor in Binary Authorization:

   gcloud --project=${ATTESTOR_PROJECT_ID} \
       container binauthz attestors create ${ATTESTOR_NAME} \
       --attestation-authority-note=${NOTE_ID} \
       --attestation-authority-note-project=${ATTESTOR_PROJECT_ID}
   

2. Verify that the attestor was created:

   gcloud --project=${ATTESTOR_PROJECT_ID} \
       container binauthz attestors list
   

The attestor you created is not yet usable without an associated PKIX key pair, which you create below.

Add an IAM role binding for the deployer project

You must add an IAM role binding for the deployer project to the attestor. This is used by Binary Authorization when it evaluates a policy to determine whether the project has permissions to access any associated attestations.

To add the IAM role binding:

gcloud --project ${ATTESTOR_PROJECT_ID} \
    container binauthz attestors add-iam-policy-binding \
    "projects/${ATTESTOR_PROJECT_ID}/attestors/${ATTESTOR_NAME}" \
    --member="serviceAccount:${DEPLOYER_SERVICE_ACCOUNT}" \
    --role=roles/binaryauthorization.attestorsVerifier

Set permissions on the Artifact Analysis note

You must also set permissions on the Artifact Analysis note you created so that it is accessible to both the deployer project and the attestor project. You do this by updating the IAM policy for the note to assign Viewer access to the project service accounts.

1. Generate a JSON file that contains the information needed to set the IAM policy on your note.

   cat > /tmp/iam_request.json << EOM
   {
     'resource': 'projects/${ATTESTOR_PROJECT_ID}/notes/${NOTE_ID}',
     'policy': {
       'bindings': [
         {
           'role': 'roles/containeranalysis.notes.occurrences.viewer',
           'members': [
             'serviceAccount:${ATTESTOR_SERVICE_ACCOUNT}',
             'serviceAccount:${DEPLOYER_SERVICE_ACCOUNT}'
           ]
         }
       ]
     }
   }
   EOM
   

2. Add the service account and requested access roles to the IAM policy for the note you created:

   curl -X POST  \
       -H "Content-Type: application/json" \
       -H "Authorization: Bearer $(gcloud auth print-access-token)" \
       --data-binary @/tmp/iam_request.json \
       "https://containeranalysis.googleapis.com/v1/projects/${ATTESTOR_PROJECT_ID}/notes/${NOTE_ID}:setIamPolicy"
   

Set up PKIX keys

Binary Authorization uses cryptographic keys to securely verify the identity of attestors. This ensures that only verified parties can participate in the authorization of a container image. The key pair consists of a private key, which the attestor uses to digitally sign attestations, and a public key, which you add to the attestor as stored by the Binary Authorization service.

In this tutorial, you use the recommended Elliptic Curve Digital Signature Algorithm (ECDSA) to create the key pair. You can also use RSA or PGP keys for signing. See Key purposes and algorithms for more information on signing algorithms.

The asymmetric keys generated and stored by Cloud Key Management Service (Cloud KMS) are PKIX-compliant. See Creating attestors using the CLI for more information on using PKIX keys and Cloud KMS.

Generate a key pair

A PKIX key pair consists of a private key, which the signer uses to digitally sign attestations, and a public key, which you add to the attestor. At deploy time, Binary Authorization uses this public key to verify the attestation signed by the private key.

1. Generate the private key:

   To generate a new local asymmetric PKIX key pair and store it in a file:

   PKIX (Cloud KMS)

   This step shows how to perform an attestation using keys generated and stored in Cloud Key Management Service.

   1. Set up environment variables to store information about the key pair as managed by Cloud KMS:

      If you already have a key pair, you can set these environment variables and skip the next step.

      KMS_KEY_PROJECT_ID=KMS_KEY_PROJECT_ID
      KMS_KEY_LOCATION=KMS_KEY_LOCATION
      KMS_KEYRING_NAME=KMS_KEYRING_NAME
      KMS_KEY_NAME=KMS_KEY_NAME
      KMS_KEY_VERSION=KMS_KEY_VERSION
      

      Replace the following:

      • KMS_KEY_PROJECT_ID: the ID of the project where the keys are stored
      • KMS_KEY_LOCATION: the location of the key
      • KMS_KEYRING_NAME: the name of the key ring
      • KMS_KEY_NAME: the name of the key
      • KMS_KEY_VERSION: the key version

   2. [Optional] Set up a KMS key:

      1. Create a KMS key whose public key can be stored in an attestor. This step also sets up environment variables you use below.

         To create a key and set up the environment variables:

         KMS_KEY_PROJECT_ID=${PROJECT_ID}
         KMS_KEYRING_NAME=my-binauthz-keyring
         KMS_KEY_NAME=my-binauthz-kms-key-name
         KMS_KEY_LOCATION=global
         KMS_KEY_PURPOSE=asymmetric-signing
         KMS_KEY_ALGORITHM=ec-sign-p256-sha256
         KMS_PROTECTION_LEVEL=software
         KMS_KEY_VERSION=1
         

      2. Create a KMS key ring:

         gcloud kms keyrings create ${KMS_KEYRING_NAME} \
           --location ${KMS_KEY_LOCATION} \
           --project ${KMS_KEY_PROJECT_ID}