sudo apt-get install open-iscsi    

vim /etc/iscsi/iscsid.conf

and change it to:

node.session.auth.authmethod = CHAP
# make sure user and password is same with iscsi-target
node.session.auth.username = <user_name>  
node.session.auth.password = <user password> 

sudo iscsiadm -m discovery -t sendtargets -p <iscsitarget ip addr>
sudo iscsiadm -m node --login

other useful command:

sudo iscsiadm -m node -o show
sudo iscsiadm -m session -o show

Then, you could find the new patiition:

$ more /proc/partitions    

You could use it as a normal partition, create file system and formation, or provide it to QEMU or Libvirt.

sudo iscsiadm -m node --logout