LetsEncrypt: Create SSL Certificate

apt install snapd

snap install core
snap refresh core

snap install --classic certbot

certbot certonly --manual --preferred-challenges dns \
# domain.com | www.domain.com
-d domain.com \
# For one host certificate
-d xxx.domain.com \
# For wildcard certificate
-d *.domain.com

cd /etc/letsencrypt/live

This directory contains your keys and certificates.

`[cert name]/privkey.pem`  : the private key for your certificate.
`[cert name]/fullchain.pem`: the certificate file used in most server software.
`[cert name]/chain.pem`    : used for OCSP stapling in Nginx >=1.3.7.
`[cert name]/cert.pem`     : will break many server configurations, and should not be used
                 without reading further documentation (see link below).

WARNING: DO NOT MOVE OR RENAME THESE FILES!
         Certbot expects these files to remain in this location in order
         to function properly!

We recommend not moving these files. For more information, see the Certbot
User Guide at https://certbot.eff.org/docs/using.html#where-are-my-certificates.

Renewal of manual generated certificate.

NEXT STEPS:
- This certificate will not be renewed automatically. Autorenewal of --manual certificates requires the use of an authentication hook script (--manual-auth-hook) but one was not provided. To renew this certificate, repeat this same certbot command before the certificate's expiry date.