View audit logs for GKE

This page shows you how to view information about deployment status and policy enforcement in Cloud Audit Logs.

To learn more about Cloud Audit Logs user interface terminology used in this page, see Viewing logs.

You can assess your application security posture, including Binary Authorization policy enforcement across interdependent Google Cloud products in a single dashboard. To learn more, see Security monitoring.

Overview

When you use Binary Authorization to deploy a container image to Google Kubernetes Engine (GKE), GKE writes details about the deployment to the audit logs in Google Cloud Observability. These audit log entries include enforcement status messages. You can view these log entries in the Google Cloud console or at the command line using the gcloud logging read command.

For the searches later in this guide, you access Cloud Audit Logs and select the project with the events you want to view.

For general access to Cloud Audit Logs, do the following:

1. Go to the Google Cloud Observability Logging > Logs (Logs Explorer) page in the Google Cloud console:

   Go to Logs Explorer

2. Choose the Google Cloud project for which you want to view Cloud Audit Logs.

Enforcement status messages

GKE writes messages to the audit log for the following enforcement conditions:

• Blocked deployment: Deployment was blocked due to Binary Authorization policy.
• Breakglass event: Deployment bypassed policy check using breakglass mechanism. For more information, see Using breakglass.
• Fail open: Deployment was allowed because Binary Authorization backend was unavailable.
• Dry run: Deployment allowed with policy violations because dry run mode was set in the Binary Authorization policy.

Blocked deployment events in Cloud Audit Logs

When a container image is blocked because it violates a Binary Authorization policy, you can find the blocked-deployment events in Cloud Audit Logs.

Query Cloud Audit Logs for blocked deployment events

This section describes how to query Cloud Audit Logs for blocked deployment events.

gcloud logging read --order="desc" --freshness=7d \
  'resource.type="k8s_cluster"
   logName:"cloudaudit.googleapis.com%2Factivity"
   (protoPayload.methodName="io.k8s.core.v1.pods.create" OR
    protoPayload.methodName="io.k8s.core.v1.pods.update")
   protoPayload.response.status="Failure"
   (protoPayload.response.reason="VIOLATES_POLICY" OR
   protoPayload.response.reason="Forbidden")'

Breakglass events in Cloud Audit Logs

Binary Authorization enables you to override the policy using a breakglass label in the Pod specification. When images are deployed with breakglass, Binary Authorization logs breakglass events in Cloud Audit Logs. The following section describes how you can query for these events.

Query Cloud Audit Logs for pods with breakglass specified

gcloud logging read --order="desc" --freshness=7d \
  'resource.type="k8s_cluster" AND
  logName:"cloudaudit.googleapis.com%2Factivity" AND
  (protoPayload.methodName="io.k8s.core.v1.pods.create" OR
    protoPayload.methodName="io.k8s.core.v1.pods.update") AND
  "image-policy.k8s.io/break-glass"'

Fail open events in Cloud Audit Logs

Fail open occurs when a container image deployment is attempted, Binary Authorization enforcement is unavailable or times out, and the container image is allowed to deploy.

In this case, the verification result is unknown and a log entry is recorded.

Query Cloud Audit Logs fail open events

gcloud logging read --order="desc" --freshness=7d \
  'resource.type="k8s_cluster"
   logName:"cloudaudit.googleapis.com%2Factivity"
   (protoPayload.methodName="io.k8s.core.v1.pods.create" OR
    protoPayload.methodName="io.k8s.core.v1.pods.update")
   ("image-policy.k8s.io/failed-open" OR
    "imagepolicywebhook.image-policy.k8s.io/failed-open" OR
    "failed-open.validating.webhook.admission.k8s.io")'

Dry run events in Cloud Audit Logs

Dry run mode is an enforcement mode in a policy that enables non-conformant images to be deployed, but writes details about the deployment to the audit log. Dry run mode allows you to test a policy in your production environment before it goes into effect.

When a container image fails to pass the required checks in a policy, but is permitted to be deployed by dry run mode, Cloud Audit Logs contains imagepolicywebhook.image-policy.k8s.io/dry-run: "true".

Query Cloud Audit Logs for dry run events

gcloud logging read --order="desc" --freshness=7d \
  'labels."imagepolicywebhook.image-policy.k8s.io/dry-run"="true"'