CentOS + Apache + Self signed ssl certificate

Various guides are available, e.g. a short one or an official HowTo.

#Generate private key 
openssl genrsa -out ca.key 2048 

# Generate CSR 
openssl req -new -key ca.key -out ca.csr

# Generate Self Signed Key
openssl x509 -req -days 365 -in ca.csr -signkey ca.key -out ca.crt

# Copy the files to the correct locations
cp ca.crt /etc/pki/tls/certs
cp ca.key /etc/pki/tls/private/ca.key
cp ca.csr /etc/pki/tls/private/ca.csr

Original version: this creates CA certificate (?)

yum install mod_ssl

mkdir -p /etc/httpd/ssl/ && cd /etc/httpd/ssl/
 
openssl req -x509 -nodes -days $((20*365)) -newkey rsa:2048 -keyout /etc/httpd/ssl/server.key -out /etc/httpd/ssl/server.crt

Generating a 2048 bit RSA private key
..........................................+++
...........................................................+++
writing new private key to '/etc/httpd/ssl/server.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:xx
State or Province Name (full name) []:City
Locality Name (eg, city) [Default City]:City
Organization Name (eg, company) [Default Company Ltd]:XYZ, Ltd.
Organizational Unit Name (eg, section) []:
Common Name (eg, your name or your server's hostname) []:domain.name.org
Email Address []:my@emajl.com

The most important is to specify "Common name" as the fully qualified hostname (resovable by DNS), or, at least, IP address.
then add to:

vim /etc/httpd/conf.d/ssl.conf

SSLCertificateFile /etc/httpd/ssl/server.crt
SSLCertificateKeyFile /etc/httpd/ssl/server.key

To make SELinux happy, restore context:

restorecon -RvF /etc/httpd/ssl

Finally,

service httpd restart

and check your success:  
https://www.ssllabs.com/ssltest/‎