/gke-workload-security

name: gke-workload-security
description: >-
  Audits, configures, and hardens workload-level security controls for Google
  Kubernetes Engine (GKE) applications and namespaces. Covers running cluster security
  audits (`audit_cluster.sh`), configuring Workload Identity Federation (impersonation,
  KSA/GSA binding, and pod setup), enforcing Network Policies (default-deny and Dataplane
  V2 logging), isolating high-risk pods inside GKE Sandbox (`gVisor`), enforcing Pod
  Security Standards (`restricted` labeling), and mounting Secret Manager secrets via
  CSI (`SecretProviderClass`). Use when auditing cluster security posture, isolating
  namespaces, applying pod security standards, setting up Workload Identity, or
  configuring network policies and secret volume mounts. Don't use for cluster-wide
  control plane security, RBAC hardening, Binary Authorization, Shielded Nodes,
  or enabling platform-level GKE add-ons (use gke-platform-security instead).
metadata:
  category: Security

GKE Workload Security

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:**

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

2. **Bind KSA to GSA:**

    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:**

    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.

    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: v1
kind: Pod
metadata:
  name: sandboxed-pod
spec:
  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/v1
kind: SecretProviderClass
metadata:
  name: my-secret-provider
spec:
  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/v1alpha1
kind: NetworkLogging
metadata:
  nam