This project contains the demo code belonging to my talk "Why Wasm is the perfect runtime for server-side applications."

The hello world is what is says... Just a simple hello world in C# that can be compiles to a webassembly file which you can almost everywhere.

To run it on your pc install wasmtime and use the command wasmtime demo.wasm

To give it access to the filesystem use wasmtime --dir=. demo.wasm

The second demo uses Fermyon Spin to run serverless (web) applications. The C# code example creates a simple web application If you download Spin and put the .exe in the root of the Spin folder you can run it with the command spin up

The last demo (k8s) uses Kubernetes to run a webassembly container (of only 6Mb size) to run a simple webapplication. This demo uses the Spin runtime so serve the webapplication!

For my demo I created a AKS cluster in Azure and used an Azure Container Registry for my container.

Be aware that this is still in preview...

To run wasm containers on AKS you need to add a WasmNodePool:

az feature register \
    --namespace Microsoft.ContainerService \
    --name WasmNodePoolPreview

Once it's completed, the resource provider for AKS must be refreshed to pick it up.

az provider register --namespace Microsoft.ContainerService

You need to create a Wasm/Wasi node pool and this must be done from the Azure CLI (not available in de Azure portal yet). So install this extension

az extension add --name aks-preview --upgrade

After creating your AKS cluster you can create your extra WASM/WASI Node pool where your Wasm containers can run Use the following command to add the nodepool

az aks nodepool add \
    -n ${WASI_NODE_POLL} \
    -g ${RESOURCE_GROUP} \
    -c 1 \
    --cluster-name ${AKS_CLUSTER} \
    --workload-runtime WasmWasi

In the yaml folder I have 3 files to create the necessary resources in Kubernetes. First you have to install a RuntimeClass so the pod can run on the WASM/WASI node pool. The SpinRuntime.yml holds the configuration to create a kubernetes.azure.com/wasmtime-spin-v1 RuntimeClass to run Spin applications.

The spin-in-k8s.yml file creates the pod. And the service.yml file creates a service to access the pod.