1. version
kilo 2015.1.0
2. Reproduce steps
2.1 create a instance, then stop it.
[root@SBCJNailSlot3 ~(keystone_admin)]# nova list
+--------------------------------------+--------+---------+--------------+-------------+-------------------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+--------+---------+--------------+-------------+-------------------+
| 6fe59445-fb89-47ab-9ead-2476c4522a61 | njq | SHUTOFF | - | Shutdown | test=192.168.1.52 |
+--------------------------------------+--------+---------+--------------+-------------+-------------------+
2.2 resize the instance use a new flavor which it's disk less than current flavor's disk
[root@SBCJNailSlot3 ~(keystone_admin)]# nova resize 6fe59445-fb89-47ab-9ead-2476c4522a61 45
disk value in the current flavor of instance “njq” is 20
disk value in the flavor which id equal 45 is 18.
So this resize action will trigger ResizeError that msg is unable to resize disk down.
Then enter the rollback process
2.3 rollback result：
[root@SBCJNailSlot3 ~(keystone_admin)]# nova list
+--------------------------------------+--------+---------+--------------+-------------+-------------------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+--------+---------+--------------+-------------+-------------------+
| 6fe59445-fb89-47ab-9ead-2476c4522a61 | njq | ACTIVE | - | Shutdown | test=192.168.1.52 |
+--------------------------------------+--------+---------+--------------+-------------+-------------------+
Although the finally vm_state of instance will be set to stoped by heal_instance_state.
But the process often takes some time.
IMO， This process is not reasonable, and need fix.
Fix proposed to branch: master
Review: https:/