On Wed, Apr 13, 2016 at 09:41:54PM -0400, John Ferlan wrote: > > > On 04/13/2016 12:17 PM, Daniel P. Berrange wrote: > > The iSCSI block driver has a very strange approach whereby it > > does not accept options directly as part of the -drive arg, > > but instead takes them indirectly from a -iscsi arg. To make > > up -driver and -iscsi args, it takes the iSCSI target name > > and uses that as an ID value for the -iscsi arg lookup. > > > > For example, given a -drive arg that looks like > > > > -drive > > file=iscsi://192.168.122.1:3260/iqn.2013-12.com.example%3Aiscsi-chap-netpool/1,format=raw,if=none,id=drive-virtio-disk0 > > > > The iSCSI driver will try to find the -iscsi arg with an > > id of "iqn.2013-12.com.example:iscsi-chap-netpool" eg it > > expects > > > > -iscsi > > id=iqn.2013-12.com.example:iscsi-chap-netpool,user=fred,password-secret=secret0 > > > > Unfortunately this is impossible to actually do in practice > > because almost all iSCSI target names contain a ':' which > > is not a valid ID character for QEMU: > > > > $ qemu-system-x86_64: -iscsi > > id=iqn.2013-12.com.example:iscsi-chap-netpool,user=redhat,password=123456: > > Parameter 'id' expects an identifier > > Identifiers consist of letters, digits, '-', '.', '_', starting with a > > letter. > > > > So for this to work we need to remove the invalid characters > > in some manner. This patch takes the simplest possible approach > > of just converting all invalid characters into underscores. eg > > you can now use > > > > $ qemu-system-x86_64: -iscsi > > id=iqn.2013-12.com.example_iscsi-chap-netpool,user=redhat,password=123456: > > Parameter 'id' expects an identifier > > > > There is theoretically the possibility for collison with this > > approach if there were 2 iSCSI luns attached to the same VM > > with target names that clash on the escaped char: eg > > > > iqn.2013-12.com.example:iscsi-chap-netpool > > iqn.2013-12.com.example_iscsi-chap-netpool > > > > but in reality this will never happen. In addition in QEMU 2.7 > > the need to use the -iscsi arg will be removed by allowing all > > the desired options to be listed directly with -drive. IOW this > > quick stripping of invalid characters is just a short term fix > > that will ultimately go away. For this reason it is not thought > > worthwhile to invent a full collision-free escaping syntax for > > iSCSI target IDs. > > > > Signed-off-by: Daniel P. Berrange <berra...@redhat.com> > > --- > > > > Figured I'd chime in since I tripped across this today... > > I think the one thing that concerns me about this '_' approach is we'd > be "stuck" with it. Eventually if 'initiator-name' is added to the > -drive command (as well as being able to parse the 'user=' and > 'password-secret='), then needing to add -iscsi wouldn't be required for > libvirt. Whether this patch would be required after -drive is modified > was the other question rattling around. So I figured I'd see if I can > get things to work without it... > > Using the v1 of this patch series did work for libvirt if I passed the > "id=" shown above using the '_' instead of ':'; however, taking the Pino > Toscano's series in mind, I can also start a domain using the > "initiator-name=" and "id=" parameters for '-iscsi' as follows: > > ... > -object > secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-3-jaf/master-key.aes > > ... > -iscsi > id=iscsi-chap-netpool,initiator-name=iqn.2013-12.com.example,user=redhat,password-secret=virtio-disk1-ivKey0 > -drive > file=iscsi://192.168.122.1:3260/iqn.2013-12.com.example%3Aiscsi-chap-netpool/1,format=raw,if=none,id=drive-virtio-disk1 > -device > virtio-blk-pci,scsi=off,bus=pci.0,addr=0x9,drive=drive-virtio-disk1,id=virtio-disk1,bootindex=1 >
I don't believe that is doing what you think it is doing. QEMU will still be using the "iqn.2013-12.com.example:iscsi-chap-netpool" string as an ID to lookup the corresponding -iscsi arg. It will not find it because your arg uses ID of "iscsi-chap-netpool". So, the code will now be falling backk to just using the /first/ -iscsi arg in the list. IOW, if you add multiple iSCSI disks to the VM, they will all be using the first -iscsi arg, which is certainly not what we want Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
