How do you setup multiple instances of vsftpd to run on different listen ports?

I need to setup 2 different instances of vsftpd. Which will listen on 2 different ports such that one instance listens on the default port 21 and the other can listen on another port 1123. Please guide me on how to setup vsftpd to listen on 2 different ports. I have the following vsftpd.conf file:

listen=YES
anonymous_enable=NO
local_enable=YES
write_enable=YES
dirmessage_enable=YES
use_localtime=YES
xferlog_enable=YES
connect_from_port_20=YES
xferlog_file=/var/log/vsftpd.log
ftpd_banner=Welcome to the FTP Service.
chroot_local_user=YES
secure_chroot_dir=/var/run/vsftpd/empty
pam_service_name=vsftpd
rsa_cert_file=/etc/ssl/private/vsftpd.pem

There are at least 2 ways of doing this

1. run in standalone mode
   setup several different vsftpd conf files.
   In each set a different listen_port and call each with vsftpd /path/to/conf/file
   make sure to also enable standalone mode in each conf file (set listen to YES and disable vsftpd in inet/xinet)
2. using systemd.unit to control the different configuration files (using systemctl start @service notation)

In your case simply create the 2 conf files, and start both instances as per option 1