neutron-server crashes when loading *aas plugins

I confirmed it locally. Basically, neutron is broken when trying to load a service plugin using provider configuration, if at least one --config-dir option is passed in CLI. Both Mitaka and Newton are broken. The breakage is triggered by the following change in oslo.config: https://review.openstack.org/#/c/281248/2 that changed the type for config_dir option from string to list.

Fix proposed to branch: master
Review: https://review.openstack.org/320304

Reviewed: https://review.openstack.org/320304
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=7f31ccb7bbe0f78a34d704c59d0562ea10029893
Submitter: Jenkins
Branch: master

commit 7f31ccb7bbe0f78a34d704c59d0562ea10029893
Author: Ihar Hrachyshka <email address hidden>
Date: Tue May 24 10:42:10 2016 +0200

    Adopt to config_dir option being a list and not a string

    Since oslo.config 3.8.0 (that included
    Ibd0566f11df62da031afb128c9687c5e8c7b27ae), config_dir option is a list,
    not a string. While our custom provider configuration parser for
    multistring options assumes the latter.

    It makes all installations that 1) pass at least one --config-dir option
    in CLI and 2) enable any service plugin that relies on provider
    definitions, to fail to start neutron-server. For example, this affects
    any RDO Mitaka installation with *aas service plugins enabled.

    Since Newton requires >=3.9.0, we are fine to switch to the list type
    without any code to support backwards compatibility with older option
    type. For Mitaka backport, we will need to handle both cases.

    Change-Id: I10e399a852d9fba0fd1aea79a10e2e7c906e4b3c
    Closes-Bug: #1585102

Fix proposed to branch: stable/mitaka
Review: https://review.openstack.org/322196

This issue was fixed in the openstack/neutron 9.0.0.0b1 development milestone.

Reviewed: https://review.openstack.org/322196
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=263a161fc0f9bf0a1f32c7019567be69c1e68a05
Submitter: Jenkins
Branch: stable/mitaka

commit 263a161fc0f9bf0a1f32c7019567be69c1e68a05
Author: Ihar Hrachyshka <email address hidden>
Date: Tue May 24 10:42:10 2016 +0200

    Adopt to config_dir option being a list and not a string

    Since oslo.config 3.8.0 (that included
    Ibd0566f11df62da031afb128c9687c5e8c7b27ae), config_dir option is a list,
    not a string. While our custom provider configuration parser for
    multistring options assumes the latter.

    It makes all installations that 1) pass at least one --config-dir option
    in CLI and 2) enable any service plugin that relies on provider
    definitions, to fail to start neutron-server. For example, this affects
    any RDO Mitaka installation with *aas service plugins enabled.

    Since Newton requires >=3.9.0, we are fine to switch to the list type
    without any code to support backwards compatibility with older option
    type. For Mitaka backport, we will need to handle both cases.

    Mitaka changes:
    - support oslo.config 3.7.x series by falling back to using config_dir
      option to extract --config-dir argument value.

    Change-Id: I10e399a852d9fba0fd1aea79a10e2e7c906e4b3c
    Closes-Bug: #1585102
    (cherry picked from commit 7f31ccb7bbe0f78a34d704c59d0562ea10029893)

This issue was fixed in the openstack/neutron 8.2.0 release.