map_cell0 should use the main DB connection, not the API DB

[Matt Riedemann]

The nova-manage cell_v2 map_cell0 command takes a database connection argument but if not provided, like in the case of when map_cell0 is called from the simple_cell_setup command, it uses the CONF.api_database.connection option to determine the name and connection to the cell0 database, which is confusing because the cell0 DB schema is actually the main DB, not the API DB.

We'll also need to rename the DB created for cell0 in grenade and possibly devstack, i.e.:

http://git.openstack.org/cgit/openstack-dev/grenade/tree/projects/60_nova/from-newton/upgrade-nova#n8

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/newton
Review: https://review.openstack.org/420461

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/420439
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=5b44737e0c4627b796cfcf09bff5008ae06a95ff
Submitter: Jenkins
Branch: master

commit 5b44737e0c4627b796cfcf09bff5008ae06a95ff
Author: Dan Smith <email address hidden>
Date: Sun Jan 15 10:52:36 2017 -0800

    Fix the generated cell0 default database name

    This makes the default database name for cell0 be based on the
    main database name, not the api one. Before this, we would get
    a database name of nova_api_cell0 by default, intead of nova_cell0.
    This was confusing because cell0 has "main" schema inside, not "api"
    schema.

    Closes-Bug: #1656673
    Change-Id: I86797785f76c2c927a4db8fef72b8f8d986af6b9

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 15.0.0.0b3 development milestone.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Matt Riedemann (<email address hidden>) on branch: stable/newton
Review: https://review.openstack.org/420461
Reason: This is turning out to be a mess and our docs on master point out the change here, so I'm just going to drop it.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/420461
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=f9a3c3fcff89828b7df45149c2d0ee188f439e46
Submitter: Jenkins
Branch: stable/newton

commit f9a3c3fcff89828b7df45149c2d0ee188f439e46
Author: Dan Smith <email address hidden>
Date: Sun Jan 15 10:52:36 2017 -0800

    Fix the generated cell0 default database name

    This makes the default database name for cell0 be based on the
    main database name, not the api one. Before this, we would get
    a database name of nova_api_cell0 by default, intead of nova_cell0.
    This was confusing because cell0 has "main" schema inside, not "api"
    schema.

    Conflicts:
            releasenotes/notes/cells-single-migration-command-0e98d66e31e02a50.yaml
            releasenotes/notes/ocata-requires-cellv2-96bd243be874d77f.yaml

    NOTE(mriedem): The conflict is due to commit
    7c7686366b8c6b887c0d13f202bb66bee32b51a9 not being in Newton.
    The change from that commit is left here as it does provide
    more useful information about the cell0 mapping and is
    relevant to this bug fix. The ocata-requires-cellsv2 release
    note from master is deleted in this cherry pick as it's
    not relevant to Newton since cells v2 is optional in Newton.

    Closes-Bug: #1656673
    Depends-On: I4e7f6c5eaa068c98e5c4ef3feaee50d8e4f5d484
    Depends-On: Ifdcd6a572dc0b42ba852241e22f6713cd2b084b0
    Change-Id: I86797785f76c2c927a4db8fef72b8f8d986af6b9
    (cherry picked from commit b28202fb52284dfbc9a9180ac017ddd1977efbf6)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 14.0.7 release.