Gke Workload Security

GKE Workload Security

Routing Note: For Workload Identity KSA/GSA bindings, open gke-workload-identity/SKILL.md. For cluster-level security flags (--database-encryption-key, --security-posture, RBAC, Shielded Nodes, Binary Authorization), open gke-platform-security/SKILL.md.

This skill provides workflows and best practices for securing GKE workloads. It covers security auditing, Identity and Access Management (Workload Identity), Network Security (Network Policies), and Node Security.

Workflows

1. Security Audit

Assess the current security posture of your cluster using the provided audit script.

Prerequisites:

• gcloud CLI authenticated.
• jq command-line JSON processor installed.

Capabilities:

• Checks for Workload Identity.
• Verifies Network Policy is enabled.
• Checks if Shielded Nodes are enabled.
• Checks if Binary Authorization is enabled.
• Checks for Private Cluster configuration.

Command:

scripts/audit_cluster.sh <cluster-name> <region> <project-id>

2. Configure Workload Identity

Workload Identity allows Kubernetes Service Accounts (KSAs) to impersonate Google Service Accounts (GSAs). This is the recommended method for workloads to access Google Cloud APIs.

Steps:

1. Create Namespace and KSA:

   bash

   kubectl create namespace workload-identity-test-nskubectl create serviceaccount <ksa-name> \    --namespace workload-identity-test-ns

2. Bind KSA to GSA:

   bash

   gcloud iam service-accounts add-iam-policy-binding <gsa-name>@<project-id>.iam.gserviceaccount.com \    --role roles/iam.workloadIdentityUser \    --member "serviceAccount:<project-id>.svc.id.goog[workload-identity-test-ns/<ksa-name>]"

3. Annotate KSA:

   bash

   kubectl annotate serviceaccount <ksa-name> \    --namespace workload-identity-test-ns \    iam.gke.io/gcp-service-account=<gsa-name>@<project-id>.iam.gserviceaccount.com

4. Verify Example Pod: Use existing asset assets/workload-identity-pod.yaml to test the configuration. Update the <ksa-name> in the file first.

   bash

   kubectl apply -f assets/workload-identity-pod.yaml -n workload-identity-test-ns

3. Implement Network Policies

Control traffic flow between Pods using Network Policies. By default, all traffic is allowed.

Enable Network Policy Enforcement:

gcloud container clusters update <cluster-name> \    --update-addons=NetworkPolicy=ENABLED \    --region <region>

[!NOTE] If your cluster uses Dataplane V2 (--enable-dataplane-v2), Network Policy enforcement is built-in and this step is not required (and may fail).

Apply Default Deny Policy: Isolate namespaces by denying all ingress and egress traffic by default.

Replace <target-namespace> with the namespace you want to isolate.

kubectl apply -f assets/default-deny-netpol.yaml -n <target-namespace>

4. GKE Sandbox (gVisor) Pod Isolation

Run untrusted workloads in a sandbox for extra kernel isolation. (Note: Enabling Shielded Nodes (--enable-shielded-nodes) and GKE Sandbox (--enable-gke-sandbox) at the cluster control plane level are platform-level actions covered in the gke-platform-security skill.)

Run a Sandboxed Pod: Add runtimeClassName: gvisor to your Pod spec:

apiVersion: v1kind: Podmetadata:  name: sandboxed-podspec:  runtimeClassName: gvisor  containers:  - name: app    image: nginx

5. Pod Security Standards

Enforce security policies on namespaces using labels.

Enforce Restricted Profile:

kubectl label --overwrite ns <namespace> \    pod-security.kubernetes.io/enforce=restricted \    pod-security.kubernetes.io/enforce-version=latest

[!NOTE] Using latest ensures you use the policies corresponding to the cluster's current version. You can pin it to a specific version (e.g., v1.30) to lock down the namespace to policies of a specific release.

6. Secret Manager Integration (CSI Driver)

Mount secrets from Google Cloud Secret Manager directly as volumes in your pods.

Prerequisites: Secret Manager CSI driver must be enabled on the cluster.

Example SecretProviderClass:

apiVersion: secrets-store.csi.x-k8s.io/v1kind: SecretProviderClassmetadata:  name: my-secret-providerspec:  provider: gcp  parameters:    secrets: |      - resourceName: "projects/<project-id>/secrets/my-secret/versions/latest"        fileName: "my-secret-file"

Example Pod Spec excerpt:

spec:  containers:    - name: my-app      volumeMounts:        - name: secrets-store-inline          mountPath: "/mnt/secrets"          readOnly: true  volumes:    - name: secrets-store-inline      csi:        driver: secrets-store.csi.k8s.io        readOnly: true        volumeAttributes:          secretProviderClass: "my-secret-provider"

7. Enable Network Policy Logging

If using GKE Dataplane V2, you can log allowed and denied connections.

Steps:

1. Configure the NetworkLogging custom resource.

Example NetworkLogging Manifest:

apiVersion: networking.gke.io/v1alpha1kind: NetworkLoggingmetadata:  name: defaultspec:  cluster:    allow:      log: true      delegate: true    deny:      log: true      delegate: true

This will log connection details to Cloud Logging.

Best Practices

1. Least Privilege: Always use Workload Identity with minimal IAM roles. Avoid using Node default service accounts.
2. Network Isolation: Use Network Policies to restrict Pod-to-Pod communication. Enable Network Policy Logging for visibility.
3. Image Security: Use Binary Authorization to ensure only trusted images are deployed.
4. Secret Management: Use Secret Manager CSI driver instead of default Kubernetes secrets for sensitive data.
5. Pod Security: Enforce baseline or restricted Pod Security Standards on all non-system namespaces.
6. Policy Enforcement: Consider using Policy Controller (Gatekeeper) to enforce custom security and compliance policies across the cluster.

Resources

• Workload Identity Federation for GKE
• GKE Network Policies
• Pod Security Standards in GKE
• Google Secret Manager CSI Driver
• GKE Dataplane V2 Network Logging