3.1 Create a Sample App

To simulate the experience of a backend engineer deploying to your Kubernetes platform, we’ll write a small application in Go, that we want to use to deploy to a Kubernetes clyster.

Step 1 — Create App

Create a new directory in your Pulumi project called app:

mkdir platform-app

Inside that directory, add a main.go file which will serve a simple webserver that returns Hello, world!:

package main

import (

func main() {
	r := gin.New()

	r.GET("/", func(c *gin.Context) {
		c.String(http.StatusOK, "Hello, world!")

	var listenPort string

	port, defined := os.LookupEnv("LISTEN_PORT")

	if defined {
		listenPort = port
	} else {
		listenPort = "80"

	r.Run(fmt.Sprintf(":%s", listenPort))

You’ll also need to create a go.mod file inside the app directory:

go mod init platform-app

You can go test your application starts by using go run:

LISTEN_PORT=8080 go run platform-app/main.go

You should see your web server start, like so:

[GIN-debug] [WARNING] Running in "debug" mode. Switch to "release" mode in production.
 - using env:	export GIN_MODE=release
 - using code:	gin.SetMode(gin.ReleaseMode)

[GIN-debug] GET    /                         --> main.main.func1 (3 handlers)
[GIN-debug] Listening and serving HTTP on :8080

Step 2 — Create a Docker Image

Next, we need to add a Dockerfile so we can push this Image to a registry. Inside the app directory, add a `Dockerfile that looks like this:

FROM golang:buster as builder
COPY . .
RUN go mod download \
    && go build -o /app/webserver

# Runtime container
FROM scratch
COPY --from=builder /app/webserver /app/webserver

ENTRYPOINT [ "/app/webserver" ]

We’re using a Docker multi-stage build here to ensure we keep the image size as low as possible. This is the end of building our application.

Now we have our docker container, we need to deploy it to our Kubernetes cluster.