Rebuild detaches block devices when instance is still powered on

[Roman Podoliaka]

Due to the fact that rebuild detaches block devices when instance is still powered on, data written to attached volumes can possibly be lost, if it hasn't been fsynced yet.

We can prevent this by allowing instance to shut down gracefully before detaching block devices during rebuild.

[jichenjc (jichenjc)]

yes, I think we should use clean_shutdown param instead of self.driver.destroy directly

[melanie witt (melwitt)]

Review is at https://review.openstack.org/#/c/176892/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/176892
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=7fe20e96f2604d03ec6a7fa563485ffdcb5cc519
Submitter: Jenkins
Branch: master

commit 7fe20e96f2604d03ec6a7fa563485ffdcb5cc519
Author: Roman Podoliaka <email address hidden>
Date: Tue Apr 21 12:47:24 2015 +0300

    rebuild: make sure server is shut down before volumes are detached

    Currently, we detach block devices before an instance is shut down,
    which means all the data, which hasn't been fsynced yet, will possibly
    be lost.

    A tempest test is added in I1158719cb906309a29ea83460e7e35d753ad1081

    Closes-Bug: #1471216
    Related-Bug: #1440762

    Change-Id: I4846418c4dbdae5b1ac1c08e8b9ac8cea5cb2990