"Instance network is not ready yet (HTTP 400)" error raised installing Generic driver in DHSS=False mode

[Valeriy Ponomaryov]

Our CI job that installs Generic driver in DHSS=False mode fails with following error:

Devstack logs:

http://logs.openstack.org/59/418559/11/check/gate-manila-tempest-dsvm-generic-no-share-servers-ubuntu-xenial-nv/537cce1/logs/devstacklog.txt.gz#_2017-01-30_11_00_01_255

Nova API logs:

http://logs.openstack.org/59/418559/11/check/gate-manila-tempest-dsvm-generic-no-share-servers-ubuntu-xenial-nv/537cce1/logs/screen-n-api.txt.gz#_2017-01-30_10_59_57_027

Local testing shows that Nova VM just hangs in "scheduling" state and we see following error in nova conductor:
2017-01-30 19:36:53.383 ERROR nova.conductor.manager [req-2c49ef47-e147-412f-b490-071a810b0d5e admin admin] No host-to-cell mapping found for selected host manila-on-xenial. Setup is incomplete.
2017-01-30 19:36:53.388 ERROR nova.conductor.manager [req-2c49ef47-e147-412f-b490-071a810b0d5e admin admin] No cell mapping found for cell0 while trying to record scheduling failure. Setup is incomplete.

And nothing else happens.

Possible cause of the failure is merge of following commit to Nova repo:
https://review.openstack.org/#/c/319379/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/426737

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/426737
Committed: https://git.openstack.org/cgit/openstack/manila/commit/?id=8cfb1e218916ce37150cb4d5c2860ef4c95aa617
Submitter: Jenkins
Branch: master

commit 8cfb1e218916ce37150cb4d5c2860ef4c95aa617
Author: Valeriy Ponomaryov <email address hidden>
Date: Mon Jan 30 20:59:48 2017 +0300

    Fix setup of DHSS=False mode for generic driver

    By moving creation of Nova VMs to later step when Nova configuration
    is fully completed. In our case, after merge of [1] we are able
    to create Nova VMs only in "test-config" section because latest Nova
    step that is required for creation of VMs is performed in the end
    of "post-extra" section.

    [1] I8742071b55f018f864f5a382de20075a5b444a79

    Change-Id: Ib941a5551fe340b39719e3c0e701067ce83bac02
    Closes-Bug: #1660304

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/manila 4.0.0.0rc1 release candidate.