Deploy WebAssembly Apps with Gateway API and SpinKube

Introduction to Modern Kubernetes Networking

Deploying serverless WebAssembly applications on Kubernetes has never been simpler. The Gateway API revolutionizes how we expose services, eliminating the need for vendor-specific annotations. This post demonstrates how to leverage SpinKube and the Gateway API to run Spin apps efficiently.

What is SpinKube?

SpinKube, a CNCF sandbox project, enables serverless WebAssembly applications on Kubernetes without containers. It uses a containerd-shim implementation to run Spin apps directly on worker nodes. For setup instructions, visit spinkube.dev.

Understanding Gateway API

The Gateway API replaces legacy Ingress with a structured approach using GatewayClass, Gateway, and route resources. This separation empowers developers to define routing rules while admins manage infrastructure. Key benefits include:

Native support for canary rollouts
Header-based routing
Traffic mirroring capabilities

Explore the official documentation for technical details.

Setting Up Your Environment

Ensure you have these tools installed:

spin CLI (install from spinframework.dev)
Rust with wasm32-wasip1 target
kubectl and helm for Kubernetes

Building and Deploying Spin Apps

Compile your Spin apps to WebAssembly:

# Build applications
pushd apps/greeter
spin build
popd

pushd apps/prime-numbers
spin build
popd

Push artifacts to an OCI registry:

# Push to ephemeral registry
greeter_app_artifact=ttl.sh/spin-greeter:24h
spin registry push $greeter_app_artifact --build

Deploy to Kubernetes:

spin kube scaffold --from $greeter_app_artifact | kubectl apply -f -

Exposing Apps with Gateway API

Install Gateway API resources and NGINX Gateway Fabric:

# Install Gateway API CRDs
kubectl kustomize "https://github.com/nginx/nginx-gateway-fabric/config/crd/gateway-api/standard?ref=v2.3.0" | kubectl apply -f -

# Install NGINX Gateway Fabric
helm install ngf oci://ghcr.io/nginx/charts/nginx-gateway-fabric --create-namespace -n nginx-gateway

Create a Gateway resource to define entry points:

apiVersion: gateway.networking.k8s.io/v1beta1
kind: Gateway
metadata:

name: spinkube-gateway
spec:

gatewayClassName: ngf

listeners:

- protocol: HTTP

port: 80

hostname: "spin-apps.example.com"

Conclusion and Next Steps

The Gateway API simplifies exposing SpinKube applications while maintaining vendor independence. For full setup instructions, explore the GitHub repository. Start testing your apps today!