# apt # snap
# Ubuntu
sudo apt install snapd
sudo reboot

sudo snap install core; sudo snap refresh core
sudo snap install --classic certbot
sudo ln -s /snap/bin/certbot /usr/bin/certbot

# dns  cloudflare
sudo snap set certbot trust-plugin-with-root=ok
sudo snap install certbot-dns-cloudflare

mkdir -p ~/.secrets/certbot
vi ~/.secrets/certbot/cloudflare.ini
----------------------------------
# Cloudflare API token used by Certbot
dns_cloudflare_api_token = IdgrE2pGEQxdq43kQPJ8*****************
chmod 600 ~/.secrets/certbot/cloudflare.ini

#
# *.4084.live
sudo certbot certonly --dns-cloudflare \\
   --dns-cloudflare-credentials ~/.secrets/certbot/cloudflare.ini \\
   -d *.4084.live

-----------------
ubuntu@dev-project-app:~$ sudo certbot certonly --dns-cloudflare \\
>    --dns-cloudflare-credentials ~/.secrets/certbot/cloudflare.ini \\
>    -d *.4084.live
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Enter email address (used for urgent renewal and security notices)
 (Enter 'c' to cancel): [email protected]

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Please read the Terms of Service at
<https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf>. You must
agree in order to register with the ACME server. Do you agree?
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(Y)es/(N)o: Y

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Would you be willing, once your first certificate is successfully issued, to
share your email address with the Electronic Frontier Foundation, a founding
partner of the Let's Encrypt project and the non-profit organization that
develops Certbot? We'd like to send you email about our work encrypting the web,
EFF news, campaigns, and ways to support digital freedom.
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(Y)es/(N)o: Y
Account registered.
Requesting a certificate for *.4084.live
Waiting 10 seconds for DNS changes to propagate

Successfully received certificate.
Certificate is saved at: /etc/letsencrypt/live/4084.live/fullchain.pem
Key is saved at:         /etc/letsencrypt/live/4084.live/privkey.pem
This certificate expires on 2022-02-26.
These files will be updated when the certificate renews.
Certbot has set up a scheduled task to automatically renew this certificate in the background.

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If you like Certbot, please consider supporting our work by:
 * Donating to ISRG / Let's Encrypt:   <https://letsencrypt.org/donate>
 * Donating to EFF:                    <https://eff.org/donate-le>
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#     (--dry-run)
sudo certbot renew --dry-run

#(xx )
sudo certbot renew

crontab -e
-----------
# cert renewal
1 2 * * 0 sudo /usr/bin/certbot renew

cp ~/Downloads/{keypair-name.pem} ~/.ssh/AWS
chmod 600 {keypair-name.pem}

ssh -i ./{keypair-name.pem} ubuntu@{public ipv4 주소}

sudo apt update
sudo apt upgrade

sudo hostnamectl set-hostname {원하는 이름}
# 재접속

sudo timedatectl set-timezone Asia/Seoul

cd ~/.ssh
ssh-keygen

vim ~/.ssh/authorized_keys
위에서 복사한 id_rsa.pub 내용을 붙여넣고 저장한다.