转自：http://blog.csdn.net/ugyn109/article/details/8126059
问题
OpenStack中很容易导致数据库和真实状态不一致的情况。因为OpenStack中操作基本都是分步完成的，从api接受请求到调度再到具体的操作节点，每一步都有可能更新数据库状态，如果哪一个出错就会直接抛出异常导致整个操作链中断，然后数据库就处于上一个操作后的更新状态。比较典型的就是删除实例，如果在nova-compute出错那这个实例的状态就可能永远处于deleting状态了。
现在我遇到这样一个问题，我有一个Volume挂载在一个实例上，但是不知道什么原因，这个Volume与这个实例的联系断了，在nova-volume通过tgtadm查看发现已经没有客户端连接到该Volume了。但是数据库中该记录还在，这导致以下结果：
1) 删除实例时无法删除，提示“Stderr: 'iscsiadm: No records found'”
2) 无法从实例卸载Volume 。于是只能直接操作数据库了。
与Volume相关的表
数据库中与Volume直接相关的几个表如下所示
操作Volume时数据库的相关数据变化
新建Volume：
- select * from volumes where id = 40\G
- *************************** 1. row ***************************
- created_at: 2012-10-29 07:00:23
- updated_at: 2012-10-29 07:00:25
- deleted_at: NULL
- deleted: 0
- id: 40
- ec2_id: NULL
- user_id: 397dd3be88b6492caa88521502b07617
- project_id: c6159a4f3dd34a2b83527499a40dbd2b
- host: store2.sigsit.org
- size: 20
- availability_zone: nova
- instance_id: NULL
- mountpoint: NULL
- attach_time: NULL
- status: available
- attach_status: detached
- scheduled_at: 2012-10-29 07:00:23
- launched_at: 2012-10-29 07:00:25
- terminated_at: NULL
- display_name: test
- display_description:
- provider_location: 10.61.2.14:3260,5 iqn.2010-10.org.openstack:volume-00000028 1
- provider_auth: NULL
- snapshot_id: NULL
- volume_type_id: NULL
- select * from volume_metadata where volume_id = 40\G
- select * from iscsi_targets where volume_id = 40\G
- *************************** 1. row ***************************
- created_at: 2012-09-24 09:00:36
- updated_at: 2012-10-29 07:00:24
- deleted_at: NULL
- deleted: 0
- id: 205
- target_num: 5
- host: store2.sigsit.org
- volume_id: 40
- select * from block_device_mapping where volume_id = 40\G
- select * from sm_volume where id = 40\G
将该Volume挂载到一个实例后：
- select * from volumes where id = 40\G
- *************************** 1. row ***************************
- created_at: 2012-10-29 07:00:23
- updated_at: 2012-10-29 11:55:36
- deleted_at: NULL
- deleted: 0
- id: 40
- ec2_id: NULL
- user_id: 397dd3be88b6492caa88521502b07617
- project_id: c6159a4f3dd34a2b83527499a40dbd2b
- host: store2.sigsit.org
- size: 20
- availability_zone: nova
- instance_id: 70
- mountpoint: /dev/vdc
- attach_time: NULL
- status: in-use
- attach_status: attached
- scheduled_at: 2012-10-29 07:00:23
- launched_at: 2012-10-29 07:00:25
- terminated_at: NULL
- display_name: test
- display_description:
- provider_location: 10.61.2.14:3260,5 iqn.2010-10.org.openstack:volume-00000028 1
- provider_auth: NULL
- snapshot_id: NULL
- volume_type_id: NULL
- select * from volume_metadata where volume_id = 40\G
- select * from iscsi_targets where volume_id = 40\G
- *************************** 1. row ***************************
- created_at: 2012-09-24 09:00:36
- updated_at: 2012-10-29 07:00:24
- deleted_at: NULL
- deleted: 0
- id: 205
- target_num: 5
- host: store2.sigsit.org
- volume_id: 40
- select * from block_device_mapping where volume_id = 40\G
- *************************** 1. row ***************************
- created_at: 2012-10-29 11:55:36
- updated_at: NULL
- deleted_at: NULL
- deleted: 0
- id: 49
- instance_id: 70
- device_name: /dev/vdc
- delete_on_termination: 0
- virtual_name: NULL
- snapshot_id: NULL
- volume_id: 40
- volume_size: NULL
- no_device: NULL
- connection_info: {"driver_volume_type": "iscsi", "data": {"device_path": "/dev/disk/by-path/ip-10.61.2.14:3260-iscsi-iqn.2010-10.org.openstack:volume-00000028-lun-1", "target_discovered": false, "target_iqn": "iqn.2010-10.org.openstack:volume-00000028", "target_portal": "10.61.2.14:3260", "volume_id": 40, "target_lun": 1}}
- select * from sm_volume where id = 40\G
- select * from instances where id = 70\G
- *************************** 1. row ***************************
- created_at: 2012-09-10 02:32:36
- updated_at: 2012-09-12 10:43:48
- deleted_at: NULL
- deleted: 0
- id: 70
- internal_id: NULL
- user_id: 397dd3be88b6492caa88521502b07617
- project_id: c6159a4f3dd34a2b83527499a40dbd2b
- image_ref: 6c239063-9d2a-41ce-9612-bfe3564cc203
- kernel_id:
- ramdisk_id:
- server_name: NULL
- launch_index: 0
- key_name: NULL
- key_data: NULL
- power_state: 1
- vm_state: active
- memory_mb: 1024
- vcpus: 1
- hostname: jiangyong-win7
- host: stack6.sigsit.org
- user_data:
- reservation_id: r-h1yqckm4
- scheduled_at: 2012-09-10 02:32:37
- launched_at: 2012-09-10 02:32:48
- terminated_at: NULL
- display_name: jiangyong-win7
- display_description: jiangyong-win7
- availability_zone: NULL
- locked: 0
- os_type: NULL
- launched_on: stack6.sigsit.org
- instance_type_id: 19
- vm_mode: NULL
- uuid: 333f6afa-9009-40f7-a493-20b2382628b1
- architecture: NULL
- root_device_name: /dev/vda
- access_ip_v4: NULL
- access_ip_v6: NULL
- config_drive:
- task_state: NULL