A few days ago I received a request from someone who wanted to run k8s-ecr-login-renew
on a Raspberry Pi Kubernetes cluster.
Fortunately, I already had experience building Go apps for that architecture.
But what I really had no clue about was the next step: putting that executable into a Docker image.
Looking around online, I found a few articles that recommended installing an experimental version of Docker,
and then running the docker buildx... command to build for different platforms.
I also found that the Alpine image in Docker Hub has published ARM-based versions.
I don't know why, but I decided to just try building an image without installing the experimental feature.
I'm happy I did that, because it turned out to be quite easy to build.
Here's how I did it:
- Start with a regular (x86) image for building the Go app
- Set environment variables for Go to build for the ARM processor
- Build the Go app for ARM:
RUN env GOOS=linux GOARCH=arm GOARM=5 go build... - Switch to an ARM-based Alpine linux image:
arm32v7/alpine - Copy the executable from the build image to the Alpine image
You can see this all in action in the Dockerfile-arm file in the
project repo.
And that is it, super easy!