Prepare to set up with the GKE Gateway API

This guide tells you how to prepare the environment for using the Google Kubernetes Engine Gateway API with Traffic Director. At a high level, you need to perform the following steps:

Enable the required Google Cloud API services.
Deploy a GKE cluster.
Configure IAM permissions.
Install the required custom resource definitions (CRDs).
Register the cluster to a fleet.
[Optional] Enable multi-cluster Services (Multi-Cluster Service Discovery).
Enable the service mesh.

If you are not using GKE, use the service routing APIs and create a Mesh resource.

Before you begin

Make sure that the components of your deployment meet these requirements:

GKE must be version 1.20 or later.
Only data planes with the xDS version 3 API and later are supported.
- Minimum Envoy version of 1.20.0
- Minimum gRPC bootstrap generator version of v0.14.0
GKE clusters must be in VPC-native (Alias IP) mode.
Self-managed Kubernetes clusters on Compute Engine, as opposed to GKE are not supported.
Any additional restrictions listed for the Gateway functionality on GKE apply to the Traffic Director integration with the GKE Gateway API.
The service account for your GKE nodes and Pods must have permission to access the Traffic Director API. For more information on the required permissions, see Enabling the service account to access the Traffic Director API.
Per-project resource usage and backend service quota limitations apply.

Enable the required Google Cloud API services

Run the following command to enable the required APIs, if they are not already enabled in your project:

gcloud services enable --project=PROJECT_ID \
  container.googleapis.com \
  gkehub.googleapis.com \
  multiclusteringress.googleapis.com \
  trafficdirector.googleapis.com \
  networkservices.googleapis.com

If you plan to include more than one cluster in your fleet, enable the multiclusterservicediscovery API:
```
gcloud services enable --project=PROJECT_ID \
   multiclusterservicediscovery.googleapis.com
```

Deploy a GKE cluster

Use these instructions to deploy a GKE cluster.

Create a GKE cluster called gke-1 in the us-west1-a zone:
```
gcloud container clusters create gke-1 \
  --zone=us-west1-a \
  --enable-ip-alias \
  --workload-pool=PROJECT_ID.svc.id.goog \
  --scopes=https://www.googleapis.com/auth/cloud-platform \
  --enable-mesh-certificates \
  --release-channel=regular \
  --project=PROJECT_ID
```
- --enable-ip-alias: This flag creates a VPC-native cluster and makes the Pods' IP addresses routable within the VPC network.
- --workload-pool: This flag lets your cluster participate in the project's workload identity pool.
- --scopes: This flag specifies the OAuth scopes assigned to the cluster nodes.
- --release-channel: This flag designates the regular channel.
- --enable-mesh-certificates: This flag enables Traffic Director's auto mTLS feature if it potentially becomes available in the future.

Get the cluster credentials:

gcloud container clusters get-credentials gke-1 --zone=us-west1-a

Rename the cluster context:

kubectl config rename-context gke_PROJECT_ID_us-west1-a_gke-1 gke-1

Configure the IAM permissions for the data plane

For this demonstration deployment, you grant the Traffic Director client role roles/trafficdirector.client to all authenticated users, including all service accounts, in the GKE cluster. This IAM role is required to authorize Traffic Director clients in the data plane, such as Envoys, to receive configuration from Traffic Director.

If you do not want to grant the client role to all authenticated users and prefer to restrict the role to service accounts, see the GKE workload identity guide to set up a specialized Kubernetes service account with the role roles/trafficdirector.client for your services.

Grant the client role to the service accounts:

gcloud projects add-iam-policy-binding PROJECT_ID \
  --member "group:PROJECT_ID.svc.id.goog:/allAuthenticatedUsers/" \
  --role "roles/trafficdirector.client"

Install the required custom resource definitions

Install the custom resource definitions (CRDs) required for using the Gateway API with Traffic Director:

kubectl apply -k "github.com/kubernetes-sigs/gateway-api/config/crd/experimental?ref=v0.6.0"

kubectl kustomize "https://github.com/GoogleCloudPlatform/gke-networking-recipes.git/gateway-api/config/mesh/crd" \
| kubectl apply -f -

Verify that required CRDs are installed automatically in the cluster by running the following command:

kubectl get crds

The output lists the following CRDs and others not related to the Gateway API, all with different creation dates:

NAME                                             CREATED AT
gatewayclasses.gateway.networking.k8s.io                           2023-08-08T05:29:03Z
gateways.gateway.networking.k8s.io                                 2023-08-08T05:29:03Z
grpcroutes.gateway.networking.k8s.io                               2023-08-08T05:29:03Z
httproutes.gateway.networking.k8s.io                               2023-08-08T05:29:03Z
referencegrants.gateway.networking.k8s.io                          2023-08-08T05:29:04Z
tcproutes.gateway.networking.k8s.io                                2023-08-08T05:29:04Z
tdgrpcroutes.net.gke.io                                            2023-08-08T05:29:23Z
tdmeshes.net.gke.io                                                2023-08-08T05:29:23Z
tlsroutes.gateway.networking.k8s.io                                2023-08-08T05:29:05Z
udproutes.gateway.networking.k8s.io                                2023-08-08T05:29:05Z

The custom resources tdmeshes.net.gke.io and tdgrpcroutes.net.gke.io are installed in the previous step.

The CRDs that are part of the net.gke.io API group are specific to GKE. These resources are not part of the OSS Gateway API implementation, which is in the networking.k8s.io API group.

Register the cluster to a fleet

After the cluster is successfully created, you must register the cluster to a fleet. Registering your cluster to a fleet lets you selectively enable features on the registered cluster.

gcloud container hub memberships register gke-1 \
  --gke-cluster us-west1-a/gke-1 \
  --location global \
  --project=PROJECT_ID

Confirm that the cluster is registered with the fleet:

gcloud container hub memberships list --project=PROJECT_ID

The output is similar to the following:

NAME   EXTERNAL_ID
gke-1  657e835d-3b6b-4bc5-9283-99d2da8c2e1b

(Optional) Enable Multi-Cluster Service Discovery

The Multi-Cluster Service Discovery feature lets you export cluster local services to all clusters registered to the fleet. This step is optional if you don't plan to include more than one cluster in your fleet.

Enable Multi-Cluster Service Discovery:

gcloud container hub multi-cluster-services enable \
  --project PROJECT_ID

Grant the Identity and Access Management (IAM) role required for Multi-Cluster Service Discovery:

gcloud projects add-iam-policy-binding PROJECT_ID \
  --member "serviceAccount:PROJECT_ID.svc.id.goog[gke-mcs/gke-mcs-importer]" \
  --role "roles/compute.networkViewer"

Confirm that Multi-Cluster Service Discovery is enabled for the registered cluster. It might take several minutes for all of the clusters to be displayed:

gcloud container hub multi-cluster-services describe --project=PROJECT_ID

You should see the memberships for gke-1, which are similar to the following:

createTime: '2021-04-02T19:34:57.832055223Z'
membershipStates
  projects/PROJECT_NUM/locations/global/memberships/gke-1:
    state:
      code: OK
      description: Firewall successfully updated
      updateTime: '2021-05-27T11:03:07.770208064Z'
name: projects/PROJECT_NUM/locations/global/features/multiclusterservicediscovery
resourceState:
  state: ACTIVE
spec: {}
updateTime: '2021-04-02T19:34:58.983512446Z'

Enable the Traffic Director GKE service mesh

In this section, you enable the service mesh.

Enable the Traffic Director GKE service mesh on the cluster that you registered with your fleet:

gcloud container hub ingress enable \
--config-membership=projects/PROJECT_ID/locations/global/memberships/gke-1 \
  --project=PROJECT_ID

Confirm that the feature is enabled:

gcloud container hub ingress describe --project=PROJECT_ID

You should see output similar to the following:

createTime: '2021-05-26T13:27:37.460383111Z'
membershipStates:
  projects/PROJECT_NUM/locations/global/memberships/gke-1:
    state:
      code: OK
      updateTime: '2021-05-27T15:08:19.397896080Z'
resourceState:
 state: ACTIVE
spec:
  multiclusteringress:
    configMembership: projects/PROJECT_ID/locations/global/memberships/gke-1
state:
  state:
    code: OK
    description: Ready to use
    updateTime: '2021-05-26T13:27:37.899549111Z'
updateTime: '2021-05-27T15:08:19.397895711Z'

Grant the following Identity and Access Management (IAM) roles, which are required by the Gateway API controller:

roles/container.developer — This role allows the controller to manage in-cluster Kubernetes resources.
roles/compute.networkAdmin — This role allows the controller to manage Traffic Director service mesh configurations.

export PROJECT_NUMBER=$(gcloud projects describe PROJECT_ID --format="value (projectNumber)")

gcloud projects add-iam-policy-binding PROJECT_ID \
  --member "serviceAccount:service-${PROJECT_NUMBER}@gcp-sa-multiclusteringress.iam.gserviceaccount.com" \
  --role "roles/container.developer"

gcloud projects add-iam-policy-binding PROJECT_ID \
  --member "serviceAccount:service-${PROJECT_NUMBER}@gcp-sa-multiclusteringress.iam.gserviceaccount.com" \
  --role "roles/compute.networkAdmin"

What's next

To set up an example deployment, read these guides: