[Liferay] Install SSL certificate on Apache for Liferay portal

You need enable ssl mod of Apache before follow this guide
sudo a2enmod ssl
1. Setup SSL on Apache2 (Unauthenticated SSL Certificates)
S1. Generating a Certificate Signing Request (CSR)
To generate the keys for the Certificate Signing Request (CSR)
openssl genrsa -des3 -out server.key 2048
Now create the insecure key, the one without a passphrase, and shuffle the key names:
openssl rsa -in server.key -out server.key.insecure
mv server.key server.key.secure
mv server.key.insecure server.key
The insecure key is server.key, we can use this file to generate the CSR without passphrase.
To create the CSR, run the following command at a terminal prompt:
openssl req -new -key server.key -out server.csr
If you enter the correct passphrase, it will prompt you to enter Company Name, Site Name, Email Id, etc. Once you enter all these details, your CSR will be created and it will be stored in the server.csr file.