Issuing and installing an SSL certificate with Let's Encrypt (Certbot)

$ sudo apt remove certbot

$ sudo snap install --classic certbot
Download snap "core20" (634) from channel "stable"            12%  190kB/s 4m56s
Download snap "certbot" (500) from channel "stable"            5%  187kB/s 4m14s
certbot 1.7.0 from Certbot Project (certbot-eff✓) installed

// Apache
$ sudo certbot --apache

// Nginx
$ sudo certbot --nginx

$ sudo certbot --apache
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator apache, Installer apache
Enter email address (used for urgent renewal and security notices)
 (Enter 'c' to cancel): [email address]

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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 at
https://acme-v02.api.letsencrypt.org/directory
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(A)gree/(C)ancel: A

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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

No names were found in your configuration files. Please enter in your domain
name(s) (comma and/or space separated)  (Enter 'c' to cancel): [domain name]

Obtaining a new certificate
Performing the following challenges:
http-01 challenge for [domain name]
Enabled Apache rewrite module
Waiting for verification...
Cleaning up challenges
Created an SSL vhost at /etc/apache2/sites-available/000-default-le-ssl.conf
Enabled Apache socache_shmcb module
Enabled Apache ssl module
Deploying Certificate to VirtualHost /etc/apache2/sites-available/000-default-le-ssl.conf
Enabling available site: /etc/apache2/sites-available/000-default-le-ssl.conf
Enabled Apache rewrite module
Redirecting vhost in /etc/apache2/sites-enabled/000-default.conf to ssl vhost in /etc/apache2/sites-available/000-default-le-ssl.conf

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Congratulations! You have successfully enabled https://[domain name]
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Subscribe to the EFF mailing list (email: [email]).

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/[domain name]/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/[domain name]/privkey.pem
   Your cert will expire on 2020-12-03. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot again
   with the "certonly" option. To non-interactively renew *all* of
   your certificates, run "certbot renew"
 - Your account credentials have been saved in your Certbot
   configuration directory at /etc/letsencrypt. You should make a
   secure backup of this folder now. This configuration directory will
   also contain certificates and private keys obtained by Certbot so
   making regular backups of this folder is ideal.
 - 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

$ sudo certbot renew --dry-run

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** DRY RUN: simulating 'certbot renew' close to cert expiry
**          (The test certificates below have not been saved.)

Congratulations, all renewals succeeded. The following certs have been renewed:
  /etc/letsencrypt/live/[domain name]/fullchain.pem (success)
** DRY RUN: simulating 'certbot renew' close to cert expiry
**          (The test certificates above have not been saved.)
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.....

/etc/crontab/
/etc/cron.*/*
$ systemctl list-timers

$ sudo systemctl list-timers
NEXT                        LEFT          LAST                        PASSED       UNIT                         ACTIVATES
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Fri 2020-09-04 22:58:00 KST 2h 2min left  n/a                         n/a          snap.certbot.renew.timer     snap.certbot.renew.service
.....