-----Original Message----- From: Daniel P. Berrange [mailto:berrange@redhat.com] Sent: Wednesday, November 18, 2009 4:12 PM To: Iyer, Shyam Cc: dallan@redhat.com; Bellad, Sudhir; libvir-list@redhat.com; Domsch, Matt; KM, Paniraja Subject: Re: [libvirt] Re: [Patch v0.4] iSCSI Multi-IQN (Libvirt Support)
On Wed, Nov 18, 2009 at 04:01:53PM +0530, Shyam_Iyer@Dell.com wrote:
-----Original Message----- From: Daniel P. Berrange [mailto:berrange@redhat.com] Sent: Wednesday, November 18, 2009 3:50 PM To: Iyer, Shyam Cc: dallan@redhat.com; Bellad, Sudhir; libvir-list@redhat.com; Domsch, Matt; KM, Paniraja Subject: Re: [libvirt] Re: [Patch v0.4] iSCSI Multi-IQN (Libvirt Support)
On Wed, Nov 18, 2009 at 01:53:50AM +0530, Shyam_Iyer@Dell.com wrote:
Iscsiadm's -I parameter takes iface name as the parameter value and not the iqn name.
So I believe this approach could be taken -
1) Get the iqn for the corresponding iface name using the following command #iscsiadm -m iface
Example output:
[root@localhost libvirt-0.7.1-15-org]# iscsiadm -m iface default tcp,default,default,unknown iser iser,default,default,unknown bnx2i bnx2i,default,default,unknown iface1 tcp,default,default,iqn.1994-05.com.fedora:iqnBellad iface3 tcp,default,default,iqn.dell iface0 tcp,unknown,unknown,iqn.1994-05.com.fedora:iqnSudhir
Ah, so where does this mapping come from ? Does the administrator have to create the mapping between interfaces & iqns, or is this totally automatic somehow ?
Today the iface file is created by by iscsi administrators using either of the following methods
1) By hand by editing the iface parameters in /var/lib/iscsi/ifaces/<iface_file>
Iface.iscsi_ifacename = <iface name> Iface.net_ifacename = <default, eth0 etc> Iface.hwaddress = <default, mac address etc> Iface.transport_name = <tcp, bnx2i etc> Iface.initiatorname = <iqn name>
This approach isn't really useful for us, since libvirt API is intended to be usable remotely without any administrator login.
2) By using iscsiadm commands like the following # iscsiadm -m iface -I <iface_name> -o new # iscsiadm -m iface -I iface1 --op=update -n iface.initiatorname -v <iqnname>
In that case, why don't we make libvirt automatically set things up this way whenever it sees the IQN in the XML file.
We don't change the default initiatorname with libvirt/virt manager today right ? So, we haven't added any apis to manage the iface file name using libvirt as such.
But if required by virt-manager(to create a single window of management) the iface file could be constructed using libvirt apis that call the iscsiadm commands detailed in method 2)
We don't need to add any new APIs for this - just automatically add
the
mapping whenever logging into a target with a IQN that we don't already know about
How do we ensure that the iqn is not already known and libvirt is creating the corresponding iface file for the first time? That would mean searching through the IFACES_DIR which has been opposed in the thread... I guess we should assume that the iqn entered into the xml has already been checked for uniqueness ... Is that a fair assumption? To enable a user to make that unique choice virt-manager should be able to show iface file configurations. We can go to that route later by adding libvirt apis that show the already configured iface file configurations to the user ... Also, how do we go about creating unique iface filenames when automatically creating them using libvirt ?