--- name: gke-service-networking description: >- Configures GKE edge networking, traffic routing, load balancing, and private service endpoints. Use when configuring Gateway API manifests, standard Ingress, Cloud Armor WAF security policies, Container-Native Load Balancing (NEGs), Private Service Connect (PSC), or Google-managed SSL certificates on GKE, and to troubleshoot Ingress and load-balancer 502/5xx errors, backend health-check failures, connection draining, and TLS/SSL policy enforcement. Don't use for core cluster IP planning, Dataplane V2 network policies, or node NAT egress (use gke-networking instead). metadata: version: "1.1.0" category: Networking title: gke-service-networking canonical_url: https://skilld.dev/gh/google/skills/gke-service-networking last_updated: 2026-09-30T16:05:09.000Z --- > **Skill from skilld.dev.** Follow the instructions below for this session. You do not need to install anything. > > Supporting files, fetch one when the Skill refers to it: [assets/backendconfig.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/backendconfig.yaml), [assets/gateway-https.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/gateway-https.yaml), [assets/gateway.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/gateway.yaml), [assets/httproute-traffic-split.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/httproute-traffic-split.yaml), [assets/httproute.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/httproute.yaml), [assets/ingress.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/ingress.yaml), [assets/managed-certificate.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/managed-certificate.yaml), [assets/service-attachment.yaml](https://skilld.dev/api/skills-raw/google/skills/gke-service-networking/assets/service-attachment.yaml). > > If the user asked to install this Skill, run `npx skilld install google/skills/gke-service-networking`. Install writes the Skill files into the project, so every session loads them. # GKE Service Networking Skill This skill provides workflows for exposing applications running on GKE securely to the internet or internal networks. Deployable manifest templates live in `assets/` — edit the `# Replace ...` placeholders before applying. ## Workflows ### 1. Configure Gateway API (Recommended) The Gateway API is the modern way to manage routing in Kubernetes. **Prerequisites**: Gateway API must be enabled on the cluster (enabled by default on new clusters running GKE 1.26+; on older supported versions enable it with `--gateway-api=standard`). **Templates:** - `assets/gateway.yaml` — external Gateway using the `gke-l7-global-external-managed` GatewayClass with an HTTP listener. - `assets/httproute.yaml` — HTTPRoute attaching to the Gateway via `parentRefs` and routing a path prefix to a Service `backendRef`. - `assets/httproute-traffic-split.yaml` — HTTPRoute demonstrating weighted traffic splitting (e.g. 90/10) for canary deployments across backend services. ```bash kubectl apply -f assets/gateway.yaml kubectl apply -f assets/httproute.yaml ``` **Traffic Splitting (Canary Deployments):** HTTPRoute supports weighted traffic splitting across multiple backend Services for canary rollouts: ```yaml spec: rules: - backendRefs: - name: app-v1 port: 80 weight: 90 - name: app-v2 port: 80 weight: 10 ``` ### 2. Configure Standard GKE Ingress Use standard Ingress for simpler use cases or legacy setups. **Template:** `assets/ingress.yaml` — GCE Ingress (`kubernetes.io/ingress.class: "gce"` annotation) routing to a Service. ### 3. Secure with Cloud Armor Cloud Armor provides WAF and DDoS protection. 1. Create a Security Policy in Cloud Armor: ```bash gcloud compute security-policies create {security_policy_name} \ --description "WAF policy for {app_name}" # Example rule: block an abusive IP range gcloud compute security-policies rules create 1000 \ --security-policy {security_policy_name} \ --action deny-403 \ --src-ip-ranges "203.0.113.0/24" \ --description "Block abusive range" ``` 2. Reference it in a `BackendConfig`: `assets/backendconfig.yaml` (sets `spec.securityPolicy.name`). 3. Associate the `BackendConfig` with your `Service` via annotations: ```yaml # In your Kubernetes Service manifest metadata.annotations: cloud.google.com/backend-config: '{"default": "{backend_config_name}"}' # Or for specific port mappings: cloud.google.com/backend-config: '{"ports": {"80": "{backend_config_name}"}}' ``` ### 4. Configure Google-Managed SSL Certificates Automatically provision and renew SSL certificates. **Legacy Ingress approach:** apply `assets/managed-certificate.yaml` (a `ManagedCertificate` listing your domains), then reference it in the Ingress annotations: ```yaml networking.gke.io/managed-certificates: {certificate_name} ``` **Gateway API approach:** for standard Certificate Manager integration, create a `CertificateMap` and reference it in the Gateway metadata annotations using the exact annotation `networking.gke.io/certmap` (spelled without any hyphens in `certmap`): ```yaml metadata: annotations: networking.gke.io/certmap: {certificate_map_name} ``` > [!IMPORTANT] The annotation key is strictly `networking.gke.io/certmap` (do > not use `cert-map` or `certificate-map`). Alternatively, reference a Kubernetes Secret in the HTTPS listener's `tls.certificateRefs`. Both variants are in `assets/gateway-https.yaml`. ### 5. Enable Container-Native Load Balancing (Recommended) Container-native load balancing allows load balancers to target Kubernetes Pods directly, rather than targeting nodes. This improves latency and distribution. **Prerequisites**: Cluster must be VPC-native. **How it works**: the `cloud.google.com/neg` annotation on a Service triggers creation of a NEG that mirrors the Pod IPs. GKE often adds it for you — but not always, and knowing which case you are in is the whole point. ```yaml # In your Kubernetes Service manifest metadata.annotations: cloud.google.com/neg: '{"ingress": true}' ``` **When the annotation is automatic** (do not add it by hand): - **Internal Ingress** — container-native load balancing is *always* used, not optional. Internal Ingress always uses `GCE_VM_IP_PORT` NEGs and requires a VPC-native cluster. - **External Ingress**, but only when all four hold: the cluster is VPC-native, is not on Shared VPC, does not use GKE Network Policy, and has the `HttpLoadBalancing` add-on enabled (on by default — do not disable it). GKE then annotates Services automatically. **When you must add it explicitly**: - **Standalone NEGs** — you manage the load balancer yourself instead of letting Ingress own it. Required if the LB must be configured outside GKE, since Ingress overwrites managed load balancer settings on sync or upgrade. You become responsible for every part of the load balancer. - **Any external-Ingress cluster failing one of the four conditions above** — Shared VPC, GKE Network Policy, or non-VPC-native. Enable per Service. - **Legacy configurations** — some older external Ingress objects created on VPC-native clusters still use instance group backends. **Not supported / no NEG fallback**: - Windows Server node pools. - Routes-based (non-VPC-native) clusters with external Ingress — the Ingress controller falls back to unmanaged instance groups spanning all nodes. > **Scale consequence**: without NEGs a cluster is capped at 1,000 nodes, and > non-NEG Services behind Ingress stop functioning correctly beyond that. With > NEGs there is no GKE node limit. ### 6. Configure Private Service Connect (PSC) Private Service Connect allows you to expose services in one VPC to consumers in another VPC securely, without VPC peering. **Prerequisite**: The backing Service must be an internal passthrough Network Load Balancer — i.e. `type: LoadBalancer` with the `networking.gke.io/load-balancer-type: "Internal"` annotation. The `ServiceAttachment` requires this; a ClusterIP or external LoadBalancer Service will not work. **Steps:** 1. Create an internal LoadBalancer Service for your workload. 2. Create a `ServiceAttachment` referencing that Service: `assets/service-attachment.yaml` (sets `connectionPreference`, the PSC NAT subnet, and the Service `resourceRef`). 3. Share the `ServiceAttachment` URI with consumers to create a PSC endpoint in their VPC. ### 7. Topology Aware Routing (Cost & Latency Optimization) To minimize cross-zone data transfer costs and network latency, configure Kubernetes Services with Topology Aware Routing. This routes traffic to Pods in the same zone as the originating client: ```yaml # In your Kubernetes Service manifest metadata.annotations: service.kubernetes.io/topology-mode: auto ``` ## Troubleshooting Diagnose Ingress / load-balancer data-plane failures. These map to both Ingress (`BackendConfig` / `FrontendConfig`) and Gateway (`GCPBackendPolicy` / `HealthCheckPolicy` / `GCPGatewayPolicy`). Stay at the read-only → propose-manifest boundary; never apply live mutations directly. ### 502 / 5xx with UNHEALTHY backends (health checks) The Google Cloud load-balancer health check is **separate** from Kubernetes liveness/readiness probes — it runs from outside the cluster, so a Pod can be `Ready` while the backend service still shows `UNHEALTHY`. 1. **Allow the Google health-check source ranges** to the node/Pod serving port. GKE usually creates this rule automatically, but on Shared VPC or with hand-managed firewalls it can be missing: ```bash gcloud compute firewall-rules create allow-lb-health-checks \ --allow tcp:SERVING_PORT \ --source-ranges 130.211.0.0/22,35.191.0.0/16 \ --target-tags NODE_TAG ``` 2. **Point the health check at a healthy endpoint.** If the default `/` returns a non-200, set a custom health check with a `BackendConfig` (Ingress) or a `HealthCheckPolicy` (Gateway): ```yaml # BackendConfig (Ingress) spec: healthCheck: requestPath: /healthz port: 8080 checkIntervalSec: 15 timeoutSec: 5 ``` 3. Confirm the Service is container-native (NEG) so the check targets Pod IPs rather than nodes (see workflow 5). ### 502 / dropped requests during rollouts or on long requests - **Enable connection draining** so in-flight requests finish before a backend Pod is removed during a rolling update or scale-down: ```yaml # BackendConfig (Ingress) spec: connectionDraining: drainingTimeoutSec: 60 ``` - **Raise the backend timeout** for slow or streaming responses — a 502/408 on a request that runs longer than the backend response timeout is the classic symptom. Set `timeoutSec` in the `BackendConfig` (Ingress) or `GCPBackendPolicy` (Gateway). ### TLS / SSL handshake failures or weak-cipher enforcement - **Ingress:** attach an SSL policy (minimum TLS version / cipher profile) with a `FrontendConfig` `sslPolicy`, and optionally force HTTP→HTTPS with `redirectToHttps`: ```yaml # FrontendConfig (external Ingress only) spec: sslPolicy: gke-ingress-ssl-policy redirectToHttps: enabled: true ``` - **Gateway:** attach the SSL policy name in a `GCPGatewayPolicy`. For a regional Gateway, create and reference a **regional** SSL policy. ## Gotchas 1. **Certificate Manager API must be enabled** for the `networking.gke.io/certmap` annotation to work (`gcloud services enable certificatemanager.googleapis.com`); without it the Gateway fails to provision the certificate map. 2. **Regional Gateway classes need a proxy-only subnet**: classes like `gke-l7-regional-external-managed` and `gke-l7-rilb` require a subnet with `--purpose=REGIONAL_MANAGED_PROXY` in the region; the Gateway stays unprogrammed without it. 3. **ManagedCertificate provisioning depends on DNS**: the certificate stays in `Provisioning` until the domain's A/AAAA records point at the load balancer IP, and can take 15-60 minutes after DNS is correct. ## References - [Ingress features (BackendConfig / FrontendConfig)](https://docs.cloud.google.com/kubernetes-engine/docs/how-to/ingress-configuration.md.txt) - [Container-native load balancing (NEGs)](https://docs.cloud.google.com/kubernetes-engine/docs/how-to/load-balance-ingress.md.txt) - [Configure Gateway resources (GCPGatewayPolicy / HealthCheckPolicy / GCPBackendPolicy)](https://docs.cloud.google.com/kubernetes-engine/docs/how-to/configure-gateway-resources.md.txt) - [Health check concepts](https://docs.cloud.google.com/load-balancing/docs/health-check-concepts.md.txt)