After pool is introduced, cinder should support the new and old version of the driver compatible

[YaoZheng_ZTE]

   After pool is introduced in the BP https://blueprints.launchpad.net/cinder/+spec/pool-aware-cinder-scheduler,
    if the driver has not supported it, In the process, the backend name is specified as the pool name.
    But if the driver later Implemented it, pool name is the back-end driver reported. so , if we have legacy volume,
the volume 's host like is: 'HostA@BackendB#volume_backend_name'. If you migrate this volume, you will fail.

[YaoZheng_ZTE (zheng-yao1)]

We should deal with this compatibility issue, The scheme: when start volume service, we can get all volumes by the host, then
extract pool information from volume's host. If the pool is None or volume_backend_name, we call get_pool query the pool_name from driver, then modify the volume's host information.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/310367

[Huang Zhiteng (zhiteng-huang)]

Can you actually describe the steps to reproduce this bug? Looks like the only way a legacy driver would put some pool name in to volume.host is unfortunately the backendname in cinder.conf is confiugred to be 'backendname#backendname' AND THEN cinder is configured to use 'backendname' instead. Is it really a valid case?

[YaoZheng_ZTE (zheng-yao1)]

 reproduce this bug steps:
1、I have two hosts and both hosts are installed cinder-volume.
[root@2C5_10_DELL05 cinder(keystone_admin)]# cinder service-list
+------------------+-----------------------------------+------+----------+-------+----------------------------+-----------------+
| Binary | Host | Zone | Status | State | Updated_at | Disabled Reason |
+------------------+-----------------------------------+------+----------+-------+----------------------------+-----------------+
| cinder-scheduler | 2C5_10_DELL05 | nova | enabled | up | 2016-05-09T11:48:31.000000 | None |
| cinder-volume | 2C5-10_DELL01@KS3200ISCSIDriver-2 | nova | enabled | up | 2016-05-09T11:49:16.000000 | None |
| cinder-volume | 2C5-10_DELL01@lvm | nova | disabled | up | 2016-05-09T11:49:17.000000 | None |
| cinder-volume | 2C5_10_DELL05 | nova | enabled | down | 2016-05-06T03:02:08.000000 | None |
| cinder-volume | 2C5_10_DELL05@FJDXISCSIDriver-1 | nova | enabled | up | 2016-05-09T11:48:29.000000 | None |
| cinder-volume | 2C5_10_DELL05@FJDXISCSIDriver-2 | nova | enabled | up | 2016-05-09T11:48:29.000000 | None |
| cinder-volume | 2C5_10_DELL05@KS3200ISCSIDriver-1 | nova | enabled | up | 2016-05-09T11:48:29.000000 | None |
| cinder-volume | 2C5_10_DELL05@KS3200ISCSIDriver-2 | nova | enabled | up | 2016-05-09T11:48:30.000000 | None |
| cinder-volume | 2C5_10_DELL05@lvm | nova | enabled | up | 2016-05-09T11:48:32.000000 | None |
+------------------+-----------------------------------+------+----------+-------+----------------------------+-----------------+
2.The host "2C5_10_DELL05" driver use support "pools" version. I create a volume in the host.
[root@2C5_10_DELL05 cinder(keystone_admin)]# cinder show eb7e638b-8385-4c73-8b60-1c4c9e89a072
+---------------------------------------+------------------------------------------------------------------------+
| Property | Value |
+---------------------------------------+------------------------------------------------------------------------+
| attachments | [] |
| availability_zone | nova |
| bootable | false |
| consistencygroup_id | None |
| created_at | 2016-05-09T01:10:59.000000 |
| description | None |
| encrypted | False |
| ...

[OpenStack Infra (hudson-openstack)]

Change abandoned by Sean McGinnis (<email address hidden>) on branch: master
Review: https://review.openstack.org/310367
Reason: This review is > 4 weeks without comment, and failed Jenkins the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.

[Sean McGinnis (sean-mcginnis)]

Unassigning due to no activity for > 6 months.