MQ服務消息超時或者任何其他中斷實例創建或者刪除的情況，都會造成“僵死”實例的存在。也即是這個實例並不存在，或者即便存在也是有問題的，並且在Dashboard儀表盤上刪除不了。提示“you are not allowed to terminate this instance"之類的錯誤。即便提示刪除成功，實際還是在那裏死趟着。命令行同樣的問題，如下
# nova list /*列表顯示出來*/
+--------------------------------------+--------------------+--------+------------+-------------+---------------------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+--------------------+--------+------------+-------------+---------------------+
| 09dca062-c577-469f-bff5-cccbe65a5b7c | instance_name | ERROR | deleting | NOSTATE | | # nova delete 09dca062-c577-469f-bff5-cccbe65a5b7c /*嘗試命令行刪除*/
# nova list /*還是上面的顯示正在刪除任務的狀態*/
# mysql -uroot -p /*在控制節點上數據庫去看看這個實例在哪個結算節點上*/
MariaDB [(none)]> select node from nova.instances where uuid='09dca062-c577-469f-bff5-cccbe65a5b7c'; /*得到這個實例所在的計算節點*/
# ll /var/lib/nova/instances/ /*到該計算節點查看實例文件夾在不在*/
# rm -Rf 09dca062-c577-469f-bff5-cccbe65a5b7c /*在的話，給刪除*/
現在再次進入數據庫，進行多個表格刪除對應實例ID的記錄。
1. nova.instances表中，實例ID的字段名是uuid；
2. 其他外鏈表使用的是instance_uuid來引用。
MariaDB [nova]> delete from table_name where instance_uuid='09dca062-c577-469f-bff5-cccbe65a5b7c'; /*從下面的表格中一一刪除關聯的記錄*/
table_name如下：
1. security_group_instance_association，實例安全組，創建默認安全組是default，但不會記錄，如果你已經關聯了安全組，那就刪除下*/
2. instance_info_caches，實例緩存，刪除
3. block_device_mapping，實例塊存儲，默認保存了一條volume_id爲NULL的記錄，刪除之*/
4. instance_actions_events，實例操作結果，字段action_id引用下表instance_actions中的id，該表沒有instance_uuid*/
5. instance_actions，實例操作，每個操作有一個id，作爲上表instance_actions_events的action_id*/
這裏我在想，真是蛋疼，兩個表爲啥不結合爲一個表。所以只能首先在instance_actions中獲取操作id然後在events中再去刪
MariaDB [nova]> select id,action,instance_uuid from instance_actions where instance_uuid='09dca062-c577-469f-bff5-cccbe65a5b7c';
+-----+--------+--------------------------------------+
| id | action | instance_uuid |
+-----+--------+--------------------------------------+
| 380 | create | 09dca062-c577-469f-bff5-cccbe65a5b7c |
| 382 | delete | 09dca062-c577-469f-bff5-cccbe65a5b7c |
| 383 | delete | 09dca062-c577-469f-bff5-cccbe65a5b7c |
| 384 | delete | 09dca062-c577-469f-bff5-cccbe65a5b7c |
| 385 | delete | 09dca062-c577-469f-bff5-cccbe65a5b7c |
| 386 | delete | 09dca062-c577-469f-bff5-cccbe65a5b7c |
+-----+--------+--------------------------------------+MariaDB [nova]> delete from instance_actions_events where action_id='382';
MariaDB [nova]> delete from instance_actions_events where action_id='383';
MariaDB [nova]> delete from instance_actions_events where action_id='384';
MariaDB [nova]> delete from instance_actions_events where action_id='385';
MariaDB [nova]> delete from instance_actions_events where action_id='386'; /*刪除instance_action_events之後再去刪除instance_action*/
6. instance_faults，實例錯誤
7. instance_extra，沒有看錶的內容，不知道放的啥東西，只有一條記錄
8. instance_system_metadata，實例元數據，記錄蠻多的
9. instances，實例表，記錄所有實例，儀表盤的實例列表就是讀取這裏
上面的9個表格刪除完畢止之後，不要急着去刷新儀表盤，不然會提示無法獲取實例列表信息 - 蠻嚇人的！實例佔用的資源依然被佔用。
# systemctl restart openstack-nova-api openstack-nova-conductor /*重啓下服務*/
# nova list /*實例刪掉了，資源收回*/
最後如果每次都這麼手動的去搞，麻煩，那就寫個腳本：
# vim deletevm.sh
mysql -uroot -p << EOF
use nova;
delete from security_group_instance_association where instance_uuid='$1';
delete from instance_info_caches where instance_uuid='$1';delete from block_device_mapping where instance_uuid='$1';delete from instance_actions where instance_uuid='$1'; /*這個地方可能需要手工，SQL能力不強哎*/delete from instance_faults where instance_uuid='$1';delete from instance_extra where instance_uuid='$1';delete from instance_system_metadata where instance_uuid='$1';delete from instances where instance_uuid='$1';
EOF
# ./deletevm.sh instance_id /*以後用這個腳本來搞就快多了*/
# nova list /*最後可以再看看*/