ironic-dbsync fails on SQLite due to bad support of migrations

[Viktor Serhieiev]

If you try to run ironic-dbsync using default backend (SQLIte) you'll get the following error

(venv)viktors@devstack:~/ironic$ ironic-dbsync --config-file etc/ironic/ironic.conf.local
INFO [alembic.migration] Context impl SQLiteImpl.
INFO [alembic.migration] Will assume non-transactional DDL.
INFO [alembic.migration] Running upgrade None -> 2581ebaf0cb2, initial migration
INFO [alembic.migration] Running upgrade 2581ebaf0cb2 -> 21b331f883ef, Add provision_updated_at
INFO [alembic.migration] Running upgrade 21b331f883ef -> 3cb628139ea4, Nodes add console enabled
/home/viktors/ironic/.tox/venv/local/lib/python2.7/site-packages/alembic/util.py:189: UserWarning: Skipping unsupported ALTER for creation of implicit constraint
  warnings.warn(msg)
INFO [alembic.migration] Running upgrade 3cb628139ea4 -> 31baaf680d2b, Add Node instance info
INFO [alembic.migration] Running upgrade 31baaf680d2b -> 3bea56f25597, add unique constraint to instance_uuid
CRITI [ironic] NotImplementedError: No support for ALTER of constraints in SQLite dialect

[Viktor Serhieiev (vsergeyev)]

This happens because of SQLite ALTER limitations - see http://www.sqlite.org/omitted.html

[Dmitry Tantsur (divius)]

Importance - high, as it will badly affect new users, trying to follow quick start guide.

[Viktor Serhieiev (vsergeyev)]

My proposal is - to fill DB schema from models in this case. We also can use this approach for testing and initial installation on any backend, instead of running migrations. See patch on review - https://review.openstack.org/#/c/107629/

[Ruby Loo (rloo)]

Victor's change adds a new subcommand for ironic-dbsync. (name is being discussed, something like 'create').

It means possibly updating the documentation at:
- http://docs.openstack.org/developer/ironic/dev/dev-quickstart.html#exercising-the-services-locally
- step 6 of http://docs.openstack.org/developer/ironic/deploy/install-guide.html#configure-the-bare-metal-service

The default for ironic-dbsync is 'upgrade'. Do we want to leave it as that, or change it to this new subcommand?

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/107629
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=e76932a0730abfd98092b4b9cbadd3a90cb32fb6
Submitter: Jenkins
Branch: master

commit e76932a0730abfd98092b4b9cbadd3a90cb32fb6
Author: Victor Sergeyev <email address hidden>
Date: Thu Jul 17 13:13:20 2014 +0300

    Use metadata.create_all() to initialise DB schema

    There is no need to run database migration each time, when we want to
    get a new actual database schema. Running all migration scripts takes a
    long time on production databases and can be not suitable for SQLite
    because of Alembic limitation.

    Added create_schema() method, which supposes to be used for initial
    installation instead of upgrade('head').

    Partial-Bug: #1347604

    Change-Id: I039d955f051eda015bef2299122fd1f0fb5c46da

[Viktor Serhieiev (vsergeyev)]

Documentation should be fixed, befor close this bug. My English is far from perfect, so I'll be glad, if someone with good English will fix the installation docs :)

[David Shrewsbury (dshrews)]

I'll take care of the documentation.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/122802