I have written scripts for automatic creation and and renewal of LetsEncrypt certificates (incl. wildcard certificates).
I thought somebody else would find this useful:
https://github.com/aney1/certbot-domainvalidation-dynu

This repository contains everything needed to create and renew LetsEncrypt certificates (incl. wildcard certificates) on Dynu (https://www.dynu.com/). This should work on every machine that can run docker (I'm using it on a QNAP NAS). If you already have certbot installed you can also just use the scripts in the scripts folder, without docker.

Hi there Aney1

Many thanks for your brilliant work!

I've been trying to use your Docker image on a Raspberry Pi 3+ (which has ARM64 architecture) and have been getting the same kind of error that I've encountered with official Docker images that weren't ARM-compatible. I've attached the output from "docker-compose up" for you to see.

Can you please tell me whether your image is ARM-compatible - and if not, maybe you can give me instructions for creating a compatible build?

The scripts work perfectly, but the certificates are created outside Docker / Letsencrypt & I don't have sufficient knowledge to modify them so that the certificates from the script are available in Docker - so if you have any suggestions on that, this might be the simplest solution.

Thanks very much once again

Neil