Compatibility bug of open-iscsi package

1. these commands worked well with open-iscsi on ubuntu-trusty:

/:/etc/init# /etc/init.d/open-iscsi restart
/:/etc/init# iscsiadm -m discovery -t sendtargets -p {portal_ip}

2. But when I failed to re-run these commands on ubuntu-xenial:

/:/etc/init# iscsiadm -m discovery -t sendtargets -p {portal_ip}
iscsiadm: Login failed to authenticate with target
iscsiadm: discovery login to {portal_ip} rejected: initiator failed authorization

iscsiadm: Could not perform SendTargets discovery: iSCSI login failed due to authorization failure
/:/etc/init# /etc/init.d/open-iscsi restart
[ ok ] Restarting open-iscsi (via systemctl): open-iscsi.service.
/:/etc/init# iscsiadm -m discovery -t sendtargets -p {portal_ip}
iscsiadm: Login failed to authenticate with target
iscsiadm: discovery login to {portal_ip} rejected: initiator failed authorization

iscsiadm: Could not perform SendTargets discovery: iSCSI login failed due to authorization failure
/:/etc/init# iscsiadm -m discovery -t sendtargets -p {portal_ip}
iscsiadm: Login failed to authenticate with target
iscsiadm: discovery login to {portal_ip} rejected: initiator failed authorization

iscsiadm: Could not perform SendTargets discovery: iSCSI login failed due to authorization failure

3. So I try to use "service" to restart "iscsid" on xenial and it was worked.

/:/etc/init# service iscsid restart
/:/etc/init# iscsiadm -m discovery -t sendtargets -p {portal_ip}
{portal_ip}:3260,1041 iqn.1992-08.com.netapp:stflon0201
{portal_ip}:3260,1042 iqn.1992-08.com.netapp:stflon0201

Conclusion:
And open-iscsi is installed by "apt-get" and I knew these was twoo packages on different distrs. And trusty didn't have "iscsid" service. Did I miss anything? What is a compatible way to setup iscsi disks?

I found these are two services: open-iscsi and iscsid

On trusty, open-iscsi is 'Starts and stops the iSCSI initiator services and logs into default targets'. But open-iscsi is 'Login to default iSCSI targets at boot and log out of all iSCSI targets at shutdown' on xenial. However, iscsid is 'The iSCSI initiator daemon takes care of monitoring iSCSI connections to targets. It is also the daemon providing the interface for the iscisadm tool to talk to when administering iSCSI connections.' on xenial.

Could we set same service name to maintain open-iscsi functionality?