[HEADS-UP] systemd for F14 - the next steps

Cole Robinson crobinso at redhat.com
Tue Jul 20 12:01:40 UTC 2010


On 07/19/2010 06:41 PM, Hans de Goede wrote:

>>
>> In a systemd world we can fix this in a much nicer way:
>> libvirtd.service would just have a "Wants: iscsid.service" in it. That
>> way when libvirtd is started iscsid is started too. And if people use
>> iscsid in other areas too they can just add a single symlink
>> (/etc/systemd/system/multi-user.target.wants/iscsid.service →
>> /lib/systemd/system/iscsid.service) and it is started on boot, regadless
>> whether libvirtd is enabled or not.
> 
> I'm afraid that is not how the relation between libvirt and
> iscsi-initiator-utils works. I don't know exactly what libvirt needs
> iscsi-initiator-utils for, but I think it does not require
> iscsid to be running. I guess we need to involve one of the
> libvirt guys into this discussion to tell us what exactly libvirt uses
> iscsi-initiator-utils for.
> 

Libvirt allows connecting to an iscsi target, using that storage as a local
'libvirt storage pool'. AIUI all libvirt uses is iscsiadm.

Here's a list of commands it can run behind the scenes:

ISCSIADM --mode session
ISCSIADM --mode iface
ISCSIADM --mode iface --interface $IFNAME --op new
ISCSIADM --mode iface --interface $IFNAME --op update --name
iface.initiatorname --value $IQN
ISCSIADM --mode discovery --type sendtargets --portal $PORTAL
ISCSIADM --mode node --portal portal --targetname $TARGETPATH --interface
$IFACE $ACTION
ISCSIADM --mode node --portal portal --targetname $TARGETPATH $ACTION
ISCSIADM --mode session -r $SESSION -R
ISCSIADM --mode discovery --type sendtargets --portal $PORTAL

You can check the relevant code here:

http://libvirt.org/git/?p=libvirt.git;a=blob;f=src/storage/storage_backend_iscsi.c;hb=HEAD

- Cole


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