Get started using the Google Cloud CLI (GKE) (original) (raw)

Enable Binary Authorization

Set the default project

The first step is to set the default Google Cloud project used by thegcloud command:

PROJECT_ID=PROJECT_ID gcloud config set project ${PROJECT_ID}

where PROJECT_ID is the name of your project.

Enable required APIs

Enable APIs for:

Artifact Registry

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

Create a cluster with Binary Authorization enabled

Create the cluster

Create a GKE cluster with Binary Authorization enabled. 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 thegcloud container clusters create command.

To create the cluster, follow these steps:

gcloud 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.

Configure `kubectl`

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

To update the local kubeconfig file:

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

View the default policy

A policy in Binary Authorization is a set of rules that govern the deployment of container images. You can have one policy per project. By default, the policy is configured to allow all container images to be deployed.

Binary Authorization allows you to export and import a policy file in YAML format. This format reflects the structure of a policy as it is stored by the service. When you configure a policy using gcloud commands, you edit this file.

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

gcloud container binauthz policy export

By default, the file has the following contents:

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

The default rule is defined in the defaultAdmissionRulenode. evaluationMode specifies that the policy allows all attempts at image deployment. In this tutorial, you update the default rule to require attestations.

globalPolicyEvaluationModeexempts Google-managed system images from Binary Authorization enforcement.

To add an exempt image to the allowlist, add the following to the policy file:

admissionWhitelistPatterns:

namePattern: EXEMPT_IMAGE_PATH

Replace EXEMPT_IMAGE_PATH with the path to am image to exempt. To exempt additional images, add additional - namePattern entries. Learn more about admissionWhitelistPatterns.

For more information on the structure of a policy, see thePolicy YAML reference.

Create an attestor

An attestor is the verification authority that the Binary Authorization enforcer uses at deploy time to decide whether to allow GKE to deploy the corresponding signed container image. The attestor contains the public key and is typically managed by personnel in your organization who are responsible for software supply chain security.

Creating an attestor requires you to:

Create a note inArtifact Analysis to store trusted metadata used in the authorization process
Create the attestor itself in Binary Authorization and associate the note you created

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 a container image.

Create the Artifact Analysis note

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.
- attestor-note: attestor note name of your choice.
Create a JSON file in /tmp/note_payload.json that describes the Container Analysis note:
cat > /tmp/note_payload.json << EOM
{
"name": "projects/${PROJECT_ID}/notes/${NOTE_ID}",
"attestation": {
"hint": {
"human_readable_name": "Attestor Note"
}
}
}
EOM
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 $(gcloud auth print-access-token)" \
--data-binary @/tmp/note_payload.json \
"https://containeranalysis.googleapis.com/v1/projects/${PROJECT_ID}/notes/?noteId=${NOTE_ID}"
Verify that the note was created:
curl \
-H "Authorization: Bearer $(gcloud auth print-access-token)" \
"https://containeranalysis.googleapis.com/v1/projects/${PROJECT_ID}/notes/${NOTE_ID}"

Create the attestor

Now, you can create the attestor:

Create the attestor in Binary Authorization:
gcloud container binauthz attestors create ${ATTESTOR_NAME} \
--attestation-authority-note=${NOTE_ID} \
--attestation-authority-note-project=${PROJECT_ID}
Verify that the attestor was created:
gcloud container binauthz attestors list

The attestor you created is not yet usable without an associated key pair, which you create later in this guide.

Generate a key pair

Binary Authorization uses cryptographic keys to securely verify the identity of signers. This ensures that only authorized container images can be deployed. The key pair consists of a private key and a public key. Thesigner uses the private key to sign the container image digest, producing a signature that is then stored in anattestation. The public key is stored in theattestor. At deploy time, the Binary Authorization enforcer uses the attestor's public key to verify the signature in the attestation before allowing the container to deploy.

In this tutorial, you use Public-Key Infrastructure (X.509) (PKIX) format for cryptographic keys. This tutorial uses the recommended Elliptic Curve Digital Signature Algorithm (ECDSA)to generate a PKIX key pair. You can also use RSA or PGP keys for signing images.

For more information on signing algorithms, see Key purposes and algorithms.

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

PKIX (Cloud KMS)

To create the key pair in Cloud KMS, do the following:

Set up environment variables needed to create the key pair.

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

To create the keyring, run the following command:

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

To create the key, run the following command:

gcloud kms keys create ${KMS_KEY_NAME} \  
  --location ${KMS_KEY_LOCATION} \  
  --keyring ${KMS_KEYRING_NAME}  \  
  --purpose ${KMS_KEY_PURPOSE} \  
  --default-algorithm ${KMS_KEY_ALGORITHM} \  
  --protection-level ${KMS_PROTECTION_LEVEL}

To add the public key to the attestor, run the following command:
gcloud --project="${PROJECT_ID}" \
container binauthz attestors public-keys add \
--attestor="${ATTESTOR_NAME}" \
--keyversion-project="${KMS_KEY_PROJECT_ID}" \
--keyversion-location="${KMS_KEY_LOCATION}" \
--keyversion-keyring="${KMS_KEYRING_NAME}" \
--keyversion-key="${KMS_KEY_NAME}" \
--keyversion="${KMS_KEY_VERSION}"
Get the public key ID from the attestor as follows:
You can view your public key ID at any time using the command:gcloud container binauthz attestors describe <var>ATTESTOR_NAME</var>.
To save your public key ID in an environment variable, enter this command:
PUBLIC_KEY_ID=$(gcloud container binauthz attestors describe ${ATTESTOR_NAME} \
--format='value(userOwnedGrafeasNote.publicKeys[0].id)' --project ${PROJECT_ID})

PKIX (local key)

To generate a PKIX key pair, follow these steps:

Create the private key:
PRIVATE_KEY_FILE="/tmp/ec_private.pem"
openssl ecparam -genkey -name prime256v1 -noout -out ${PRIVATE_KEY_FILE}
Extract the public key from the private key:
PUBLIC_KEY_FILE="/tmp/ec_public.pem"
openssl ec -in PRIVATEKEYFILE−pubout−out{PRIVATE_KEY_FILE} -pubout -out PRIVATEKEYFILE−pubout−out{PUBLIC_KEY_FILE}
Add the public key to the attestor.
Now, add the public key you exported to the attestor so that it can be used by Binary Authorization for identity verification:
gcloud --project="${PROJECT_ID}" \
container binauthz attestors public-keys add \
--attestor="${ATTESTOR_NAME}" \
--pkix-public-key-file=${PUBLIC_KEY_FILE} \
--pkix-public-key-algorithm=ecdsa-p256-sha256
Save the public key ID.
To save the public key ID, you can copy it from the output ofpublic-keys add above. To view your attestor's public key ID after adding it to the attestor, usegcloud container binauthz attestors describe ${ATTESTOR_NAME}:

PUBLIC_KEY_ID=$(gcloud container binauthz attestors describe ${ATTESTOR_NAME} \  
  --format='value(userOwnedGrafeasNote.publicKeys[0].id)')

Configure the policy

Now, you can configure your policy. In this step, you export the policy YAML file to your local system and modify the default rule so that it requires an attestation by the attestor you defined above.

To configure the policy, follow these steps:

Create a new policy file that allows Google-maintained system images, sets theevaluationMode toREQUIRE_ATTESTATION, and adds a node namedrequireAttestationsBythat references the attestor you created:
cat > /tmp/policy.yaml << EOM
globalPolicyEvaluationMode: ENABLE
defaultAdmissionRule:
evaluationMode: REQUIRE_ATTESTATION
enforcementMode: ENFORCED_BLOCK_AND_AUDIT_LOG
requireAttestationsBy:
- projects/${PROJECT_ID}/attestors/${ATTESTOR_NAME}
name: projects/${PROJECT_ID}/policy
EOM
Import the policy YAML file into Binary Authorization:
gcloud container binauthz policy import /tmp/policy.yaml

For more information on configuring a policy, seeConfigure a policy using the gcloud CLI.

Test the policy

You can test the policy you configured above by trying to deploy a sample container image to the cluster. The policy will block deployment because the required attestation has not been made.

For this tutorial, you can use sample images from Artifact Registry. The image from Artifact Registry is located at the path us-docker.pkg.dev/google-samples/containers/gke/hello-app:1.0. The path contains a public image created by Google that contains a "Hello, World!" sample application.

First, try to deploy the image:

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

Now, verify that the deployment was blocked by Binary Authorization:

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}}'

You see a response that resembles the following:

FailedCreate: Error creating: pods POD_NAME is forbidden: admission webhook "imagepolicywebhook.image-policy.k8s.io" denied the request: Image IMAGE_NAME denied by Binary Authorization default admission rule. Image IMAGE_NAME denied by attestor ATTESTOR_NAME: No attestations found

In this output:

POD_NAME: the name of the Pod.
IMAGE_NAME: the name of the image.
ATTESTOR_NAME: the name of the attestor.

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

kubectl delete deployment hello-server

Create an attestation

An attestation is a digital document created by asigner that certifies that GKE is allowed to deploy the associated container image. The process of creating an attestation is sometimes called "signing an image." A signer can be a person or, more often, an automated process that runs when a container image is built. The signature is created using the private key from a key pair. At deploy time, the Binary Authorization enforcer uses the attestor's public key to verify the signature in the attestation.

In this tutorial, your attestation simply states that you authorize the image for deployment.

To create an attestation, follow these steps:

Set variables that store the registry path and digest of the image:

Artifact Registry

IMAGE_PATH="us-docker.pkg.dev/google-samples/containers/gke/hello-app"
IMAGE_DIGEST="sha256:37e5287945774f27b418ce567cd77f4bbc9ef44a1bcd1a2312369f31f9cce567"
IMAGE_TO_ATTEST=${IMAGE_PATH}@${IMAGE_DIGEST} 2. To create the attestation, do the following:

PKIX Cloud KMS

To create the attestation using the Cloud KMS key, run the following command:

gcloud container binauthz attestations sign-and-create \  
    --project="${PROJECT_ID}" \  
    --artifact-url="${IMAGE_TO_ATTEST}" \  
    --attestor="${ATTESTOR_NAME}" \  
    --attestor-project="${PROJECT_ID}" \  
    --keyversion-project="${KMS_KEY_PROJECT_ID}" \  
    --keyversion-location="${KMS_KEY_LOCATION}" \  
    --keyversion-keyring="${KMS_KEYRING_NAME}" \  
    --keyversion-key="${KMS_KEY_NAME}" \  
    --keyversion="${KMS_KEY_VERSION}"

PKIX (local key)

To create the attestation using the local key, do the following:

Generate the attestation payload:
gcloud container binauthz create-signature-payload \
--artifact-url=${IMAGE_TO_ATTEST} > /tmp/generated_payload.json
The payload JSON file has the following contents:
{
"critical": {
"identity": {
"docker-reference": "us-docker.pkg.dev/google-samples/containers/gke/hello-app"
},
"image": {
"docker-manifest-digest": "sha256:c62ead5b8c15c231f9e786250b07909daf6c266d0fcddd93fea
882eb722c3be4"
},
"type": "Google cloud binauthz container signature"
}
}
To sign the payload with your PKIX private key and generate a signature file, run the following command:
openssl dgst -sha256 -sign ${PRIVATE_KEY_FILE} /tmp/generated_payload.json > /tmp/ec_signature
The signature file is the signed version of the payload JSON file you created earlier in this guide.
Create and validate the attestation:
gcloud container binauthz attestations create \
--project="${PROJECT_ID}" \
--artifact-url="${IMAGE_TO_ATTEST}" \
--attestor="projects/${PROJECT_ID}/attestors/${ATTESTOR_NAME}" \
--signature-file=/tmp/ec_signature \
--public-key-id="${PUBLIC_KEY_ID}" \
--validate
Replace PUBLIC_KEY_ID with the public key id that you found inGenerate a PKIX key pair above.
The validate flag checks that the attestation can be verified by the attestor you configured in your policy.
Verify that the attestation was created:
gcloud container binauthz attestations list \
--attestor=$ATTESTOR_NAME --attestor-project=$PROJECT_ID

For more information on creating attestations, seeCreating Attestations.

Retest the policy

Again, test the policy by deploying a sample container image to the cluster. This time, you must deploy the image using the digest rather than a tag like1.0 or latest, as Binary Authorization will use the digest to look up attestations. Here, Binary Authorization allows the image to be deployed because the required attestation has been made.

To deploy the image, follow these steps:

kubectl run hello-server --image ${IMAGE_TO_ATTEST} --port 8080

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

Get started using the Google Cloud CLI (GKE) (original) (raw)

Enable Binary Authorization

Set the default project

Enable required APIs

Artifact Registry

Create a cluster with Binary Authorization enabled

Create the cluster

Configure kubectl

View the default policy

Create an attestor

Create the Artifact Analysis note

Create the attestor

Generate a key pair

PKIX (Cloud KMS)

PKIX (local key)

Configure the policy

Test the policy

Create an attestation

Artifact Registry

PKIX Cloud KMS

PKIX (local key)

Retest the policy

Configure `kubectl`