Get free SSL/TLS Certificates from Let's Encrypt

My platform: macOS + macports

Install certbot

sudo port install certbot

Write a shell script

make_cert.sh

#!/bin/sh
set -e

sudo certbot --duplicate certonly -d "*.$1" -d "$1" --manual --preferred-challenges dns-01 --server https://acme-v02.api.letsencrypt.org/directory

Usage

make_cert.sh domain.com

Configure nginx

Copy all certs to /etc/nginx/cert

On Ubuntu

vim /etc/nginx/sites-available/default

Enable ssl configuration

ssl on;
ssl_certificate /etc/nginx/cert/fullchain.pem;
ssl_certificate_key /etc/nginx/cert/privkey.pem;