One can Install Apache and Nginx using YUM Or DNF in the Selected Unix flavor whereas by default it is a non-secure sub-domain when you access.

Lets encrypt offers free SSL which can be configured to get the SSL for your domain irrespective of Private Or Public Domains. In case of Private Domains , you just need to add a text Entry to Pass the Validations.

For this I am using Oracle Cloud Instance(Always Free).

Change the Host Name using hostnamectl as below

[root@certbot ~]# hostnamectl set-hostname certbot.ramoradba.com
[root@certbot ~]# hostname

As its the Initial Login after Instance provision , run the yum update and Install Apache and/or Nginx as per your choice.

Run Yum Update and make sure everything updated without any issues.

Install Apache-httpd using yum repo.

Try Access the IP/Hostname to see the Installed Apache Default Page.

Install Nginx using Yum

Try to Access Nginx from the Browser

Enable EPEL Repo to Configure Snap and Certbot

Enable the Socket and run the below to Install certbot ,

systemctl enable --now snapd.socket

ln -s /var/lib/snapd/snap /snap

snap install certbot --classic

Restart your session to get the Certbot ,You can Configure SSL for Nginx Or Apache as below, Add an Entry in you domain controller for your IP matching with the Host Name Configured.

You can Either Configure SSL and Install Or Choose the certonly Option to Get the Certificates only, you can configure your SSL.conf as per your webserver configuration
Also In case , your System is not internet facing, You can choose the Preferred Challenges as either http or DNS You can review the Supported Challenged here https://letsencrypt.org/docs/challenge-types/

certbot --nginx -d <subdomain>.ramoradba.com
certbot --apache -d <subdomain>.ramoradba.com

Make Sure you have a Virtual_Host entry available with the domain you chose., Otherwise it will fail.

<VirtualHost *:80>
    ServerName certbot.ramoradba.com
    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

certbot --apache -d certbot.ramoradba.com

Reload your browser session to see the Installed Certificate .

Thanks for your visit, Hope you like it.