So comodo ssl is not so free, I changed it to letsencrypt.
on centos6:
wget https://dl.eff.org/certbot-auto
chmod a+x certbot-auto
./certbot-auto --apache
certbot can't read my vhosts configuretion:
No names were found in your configuration files. Please enter in your domain name(s) (comma and/or space separated) (Enter 'c' to cancel)
So we'll do it by hands. Enter 'c' in promt. Script will generate certificate files then.
My httpd.conf vhost part:
SSLCertificateKeyFile /etc/letsencrypt/keys/0001_key-certbot.pem
SSLCertificateFile /etc/letsencrypt/live/domain.com/fullchain.pem
SSLCertificateChainFile /etc/letsencrypt/live/domain.com/fullchain.pem