/gke-multitenancy

name: gke-multitenancy
description: >-
  Plans and configures multi-tenancy on GKE. Covers namespace isolation, RBAC
  planning for teams, resource quotas, LimitRanges, network isolation, and
  cost allocation. Use when designing GKE multi-tenancy, configuring GKE
  namespaces, setting up resource quotas, or isolating GKE teams. Don't use
  for single-tenant cluster configuration or general deployment instructions
  (use gke-basics or gke-app-onboarding instead).
metadata:
  category: Containers

GKE Multi-Tenancy

This reference covers enterprise multi-tenancy patterns on GKE, including namespace isolation, RBAC planning, resource quotas, and network segmentation.

> **MCP Tools:** `apply_k8s_manifest`, `get_k8s_resource`, `check_k8s_auth`, > `describe_k8s_resource`, `delete_k8s_resource`

When to Use

• Multiple teams sharing a single GKE cluster
• Isolating workloads by environment (dev/staging/prod) within one cluster
• Implementing least-privilege access control
• Cost allocation across teams or projects

Multi-Tenancy Models

| Model | Isolation | Complexity | Cost | | ----------------------------- | ------------ | ---------- | -------------- | | **Namespace-per-team** | Soft (RBAC + | Low | Lowest (shared | : : Network : : cluster) : : : Policy) : : : | **Namespace-per-environment** | Soft | Low | Low | | **Node pool-per-team** | Medium | Medium | Medium | : : (dedicated : : : : : compute) : : : | **Cluster-per-team** | Hard (full | High | Highest | : : isolation) : : :

> **Golden path recommendation**: Start with namespace-per-team for cost > efficiency. Escalate to stronger isolation only when compliance requires it.

Namespace Isolation Setup

1. Create Namespaces

kubectl create namespace team-a
kubectl create namespace team-b
kubectl label namespace team-a team=a
kubectl label namespace team-b team=b

2. RBAC Configuration

**Principle**: Grant minimal permissions per namespace. Never bind to `system:authenticated`.

# Namespace-scoped role for a team
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: team-a-developer
  namespace: team-a
rules:
- apiGroups: ["", "apps", "batch"]
  resources: ["pods", "deployments", "services", "configmaps", "jobs"]
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: team-a-developers
  namespace: team-a
subjects:
- kind: Group
  name: "team-a@example.com"  # Google Group
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: team-a-developer
  apiGroup: rbac.authorization.k8s.io

**RBAC best practices:** Use Google Groups for subject bindings. Prefer namespace-scoped Roles over ClusterRoles. See the `gke-platform-security` skill for full RBAC hardening guidance.

3. Resource Quotas

Prevent any single team from consuming all cluster resources:

apiVersion: v1
kind: ResourceQuota
metadata:
  name: team-a-quota
  namespace: team-a
spec:
  hard:
    requests.cpu: "10"
    requests.memory: "20Gi"
    limits.cpu: "20"
    limits.memory: "40Gi"
    pods: "50"
    services: "10"
    persistentvolumeclaims: "10"

4. LimitRanges

Set default and maximum resource constraints per container:

apiVersion: v1
kind: LimitRange
metadata:
  name: team-a-limits
  namespace: team-a
spec:
  limits:
  - type: Container
    default:
      cpu: "500m"
      memory: "512Mi"
    defaultRequest:
      cpu: "100m"
      memory: "128Mi"
    max:
      cpu: "4"
      memory: "8Gi"

> [!IMPORTANT] **Mandatory Defaults**: When defining `min` or `max` limits in a > `LimitRange`, you **must** also define corresponding `default` and > `defaultRequest` values. If you set a `min` or `max` without defaults, any pod > deployed without explicit resource requests/limits will be rejected by the > admission controller.

5. Network Isolation

Apply default-deny per namespace (see the `gke-workload-security` skill), then allow intra-team traffic:

# Allow same-namespace pods to talk + DNS
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-same-namespace
  namespace: team-a
spec:
  podSelector: {}
  ingress:
  - from:
    - podSelector: {}
  egress:
  - to:
    - podSelector: {}
  - to:  # Allow DNS
    - namespaceSelector: {}
      podSelector:
        matchLabels:
          k8s-app: kube-dns
    ports:
    - protocol: UDP
      port: 53

Cost Allocation

Labels for Cost Attribution

# Label namespaces for billing
kubectl label namespace team-a cost-center=engineering
kubectl label namespace team-b cost-center=data-science

GKE Cost Allocation

Enable GKE cost allocation to break down costs by namespace and label:

gcloud container clusters update <CLUSTER_NAME> --region <REGION> \
  --enable-cost-allocation

View in Cloud Billing > GKE Cost Allocation.