Comment 3 for bug 1096009

Which documentation page did you used ?

I noticed that some Cinder related install guides instructs you to install the "iscsitarget" package (that's the IET iSCSI target, instead of TGT) and enable it's user space components in "/etc/default/iscsitarget". When combined with the "cinder-volume" package, which (in Ubuntu 12.10) already depends on tgt by default, gives you two active iSCSI target daemons (yes, that's one to many).
In this case it's possible (and most likely) that the IET iSCSI target starts earlier than the TGT one and blocks the default iSCSI port (3260) that prevents TGT to successfully start. When this happens Cinder's tgt-admin commands are send to the active IET iSCSI target which doesn't work (IET & TGT are two completely different iSCSI frameworks). This doesn't effect LVM volume creation because these are separate calls from the tgt-admin ones, so volumes are created successfully as you stated.

Check if, and more important which iSCSI target daemon is active on your system

# ss -tuplen | grep 3260

It should show an active socket on tcp port 3260 with a tgtd process

If you're using Ubuntu 12.10 check if you have the package "iscsitarget" installed. Remove this and also the kernel module package "iscsitarget-dkms" if installed, after that restart all related OpenStack services or just reboot to be absolutely sure...