Let’s Encrypt on AWS can be a can of worms if you don’t know what you’re doing. Photo credit.

Introduction

Let’s Encrypt and the ACME protocol enable getting free (as in beer) TLS/SSL certificates. The main use for Let’s Encrypt is to enable HTTPS on web servers. Let’s Encrypt TLS certificates expire pretty quickly, in 3 months, but the idea is that renewal is automated so that you don’t ever really have to worry about expiration, unlike with commercial TLS certificates, which you typically need to manually renew every 12 months. Using Let’s Encrypt on AWS is in some cases a very viable option, but not so much in others. In many cases trying to use Let’s Encrypt certificates leads you down the path of Lovecraftian horrors and madness. Because “it all depends” I’ll try to explain when using Let’s Encrypt is viable in the AWS context and when you really should just give up an use certificates generated by the Amazon Certificate Manager (“ACM”) instead.