gke-cost

name: gke-cost description: >- Optimizes GKE costs, rightsizes workloads, and configures Spot VMs and CUDs. Use when optimizing GKE costs, rightsizing GKE workloads, or configuring GKE Spot VMs. Don't use for general compute class provisioning or GPU Selection (use gke-compute-classes instead). metadata: category: CloudObservabilityAndMonitoring

GKE Cost Optimization

This reference covers strategies for reducing GKE costs while maintaining the golden path security and reliability posture.

MCP Tools: get_k8s_resource, describe_k8s_resource, apply_k8s_manifest, patch_k8s_resource, get_cluster

Golden Path Cost Features

The golden path already includes cost-optimizing settings:

Cost Optimization Strategies

1. Spot VMs via ComputeClasses

Use Spot VMs for fault-tolerant workloads (60-90% cost reduction).

apiVersion: cloud.google.com/v1
kind: ComputeClass
metadata:
  name: spot-with-fallback
spec:
  activeMigration:
    optimizeRulePriority: true
  priorities:
  - machineFamily: n4
    spot: true
  - machineFamily: n4
    spot: false

Spot-suitable workloads:

Handling eviction:

spec:
  template:
    spec:
      terminationGracePeriodSeconds: 25  # Must be < 30s for Spot
      containers:
      - name: app
        lifecycle:
          preStop:
            exec:
              command: ["/bin/sh", "-c", "sleep 5"]

1.1 Direct Workload Spot Selection (NodeSelector)

For stateless or batch workloads in GKE Autopilot, you do not need to create a custom ComputeClass to use Spot VMs. You can target the built-in Spot capacity directly by adding a nodeSelector to your Pod or Deployment spec.

[!WARNING] Preemption Warning: Spot VMs are interruptible and can be preempted at any time with a 30-second notice. Workloads must be fault-tolerant and run with at least 2 replicas for high availability. Always explicitly warn users about this preemption risk when recommending Spot VMs.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: stateless-spot-app
spec:
  replicas: 2
  template:
    spec:
      nodeSelector:
        cloud.google.com/gke-provisioning: Spot
      terminationGracePeriodSeconds: 25  # Must be < 30s to allow graceful shutdown before preemption
      containers:
      - name: app
        image: <IMAGE>

2. Pod Rightsizing

Use VPA recommendations to reduce over-provisioned requests.

# 1. Deploy VPA in recommendation mode
kubectl apply -f - <<EOF
apiVersion: autoscaling.k8s.io/v1
kind: VerticalPodAutoscaler
metadata:
  name: <DEPLOYMENT>-vpa
spec:
  targetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: <DEPLOYMENT>
  updatePolicy:
    updateMode: "Off"
EOF

# 2. Wait 24+ hours for data collection

# 3. Read recommendations
kubectl get vpa <DEPLOYMENT>-vpa -o jsonpath='{.status.recommendation}'

Optimization rules:

3. Machine Type Selection

In Autopilot, machine type is managed. Use ComputeClasses to influence selection.

4. Committed Use Discounts (CUDs)

For steady-state workloads, purchase 1-year or 3-year CUDs:

• 1-year: ~20-30% discount
• 3-year: ~50-55% discount
• Applied automatically to matching usage in the region
• Purchase via Google Cloud Console > Billing > Committed use discounts

5. Cluster Management

• Stop/start dev clusters: Idle dev clusters cost money even with no workloads (control plane fee).
• Right-size node pools (Standard): Use Cluster Autoscaler with appropriate min/max.
• Multi-tenant clusters: Share a single cluster across teams instead of per-team clusters (see the gke-multitenancy skill).

Cost Monitoring

# View cluster cost breakdown (requires Cost Management API)
gcloud billing budgets list --billing-account=<BILLING_ACCOUNT> --quiet

# View node utilization
kubectl top nodes

# View pod resource usage vs requests
kubectl top pods --all-namespaces --containers

Dev/Test Cost Savings

For non-production environments, these golden path deviations are acceptable:

| Setting | Production (Golden | Dev/Test | : : Path) : : | ----------------------- | ------------------ | ----------------------------- | | Cluster mode | Autopilot | Autopilot (cheaper with fewer | : : : pods) : | Release channel | Regular | Rapid (get fixes faster) | | Private nodes | Required | Optional (simpler access) | | Monitoring components | Full suite | SYSTEM_COMPONENTS only | | Secret Manager rotation | 120s | Disabled | | Maintenance windows | Configured | Not needed |