local attach of iSCSI silently fails

[John Griffith]

When trying to do things like copy-image-volume we make an iSCSI attach on the Cinder node. However we don't actually check this attach and fail the copy operation if we can't connect (ie no access to the storage network on the cinder-volume node).

Fortunately there is info in the logs pointing out that the open-iscsi connect failed, but we unfortunately report that the image is downloaded to the volume and available even though it's not.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/30577

[Vincent Hou (houshengbo)]

https://review.openstack.org/#/c/30610/
PLZ review this one.

[Thierry Carrez (ttx)]

Pushing back to H2, please set back to H1 if this is milestone-critical (in which case the fix needs to land in master first and then be backported to milestone-proposed before tomorrow)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/31941

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/31941
Committed: http://github.com/openstack/cinder/commit/aa7fde57a37ae8e03f137e7b525cc77109cc31c1
Submitter: Jenkins
Branch: master

commit aa7fde57a37ae8e03f137e7b525cc77109cc31c1
Author: Vincent Hou <email address hidden>
Date: Thu Jun 6 16:46:52 2013 +0800

    Add the iscsi device check and exception processing.

    Before downloading the image and executing the command "qemu-img convert",
    check if the iSCSI device is still available via the command "sudo dd
    if=<device> of=/dev/null count=1". This command will raise an exception with
    the message "Input/output error", if the back-end storage is disconnected to
    the cinder-volume node, so we use it to test the availability of the storage
    device. If it is unavailable, there is no need to download the image &
    "qemu-img convert" and an exception DeviceUnavailable will be raised.

    Fixed Bug1169290.

    Change-Id: I133b4cc1bac493df073d42e240092cf2e6300454