Difficulty: intermediate
Estimated Time: 20 minutes

In this scenario you'll see how Skaffold helps when you're developing Go applications that will run in Kubernetes.

https://skaffold.dev/

Congratulations, you've finished this scenario!

Running on your laptop

If you would like to try running Skaffold on your laptop, you can install it as described in the documentation.

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Skaffold

Step 1 of 3

Write a simple Go application

Start with a very simple app that writes a line to stdout every few seconds. When this app is deployed in a Kubernetes pod, you will be able to see this output as the pod's log output. 

package main

import (
  "fmt"
  "time"
)

func main() {
    for {
        fmt.Println("hello")
        time.Sleep(5*time.Second)
    }
}

Multistage build Dockerfile

# First stage: start with a Golang base image
FROM golang:1.12-alpine3.10

# Move to the directory where the source code will live
WORKDIR /go/src/hello

# Copy the source code into the current directory
COPY hello.go .

# Get any dependencies, and compile the code
RUN CGO_ENABLED=0 go get -v ./...

# Second stage: start from an empty base image
FROM scratch

# Copy the binary from the first stage
COPY --from=0 /go/bin/hello /

# Tell Docker what executable to run by default when starting this container
ENTRYPOINT ["/hello"]

Build this image and check that it works.

docker build -t hello .

docker run -t hello

This should log output to the screen on a regular basis.

Stop this container from a second terminal.

docker stop $(docker ps --filter ancestor=hello -q)

  • See the Docker documentation for more information about filtering the results from docker ps
  • The -q parameter returns just the container ID, which can then be passed to the docker stop command.

Next step

We have a very simple application that we can run in a container. Now let's get Skaffold to run it under Kubernetes.

hello.go
Dockerfile
skaffold.yaml
k8s-pod.yaml
Terminal