Volumes are being attached to instances irrespective of their state. Which should be allowed only for ACTIVE instances.
For Boot:
root@ubuntu1204:~# nova list
+--------------------------------------+-------------------------------------------------+---------+--------------------------------+
| ID | Name | Status | Networks |
+--------------------------------------+-------------------------------------------------+---------+--------------------------------+
| 42ac132a-59b5-4384-b1f9-b4796abc9d72 | Server 42ac132a-59b5-4384-b1f9-b4796abc9d72 | BUILD | private=10.0.0.3 |
+--------------------------------------+-------------------------------------------------+---------+--------------------------------+
root@ubuntu1204:~# nova volume-list
+--------------------------------------+--------+--------------+------+-------------+--------------------------------------+
| ID | Status | Display Name | Size | Volume Type | Attached to |
+--------------------------------------+--------+--------------+------+-------------+--------------------------------------+
| ea26bd2b-b4bb-4fcf-ad1a-679e5251a5fa | in-use | None | 1 | None | 42ac132a-59b5-4384-b1f9-b4796abc9d72 |
+--------------------------------------+--------+--------------+------+-------------+--------------------------------------+
For Reboot:
root@ubuntu1204:~# nova list
+--------------------------------------+-------------------------------------------------+--------+--------------------------------+
| ID | Name | Status | Networks |
+--------------------------------------+-------------------------------------------------+--------+--------------------------------+
| 790bb025-f101-4c58-8f42-e1d80f50a170 | NOVdemoB0II0--onhost--nv-aw1st | REBOOT | private=10.0.0.9, 172.24.4.225 |
+--------------------------------------+-------------------------------------------------+--------+--------------------------------+
root@ubuntu1204:~# nova volume-list
+--------------------------------------+--------+--------------+------+-------------+--------------------------------------+
| ID | Status | Display Name | Size | Volume Type | Attached to |
+--------------------------------------+--------+--------------+------+-------------+--------------------------------------+
| ea26bd2b-b4bb-4fcf-ad1a-679e5251a5fa | in-use | None | 1 | None | 790bb025-f101-4c58-8f42-e1d80f50a170 |
+--------------------------------------+--------+--------------+------+-------------+--------------------------------------+
I don't think this is actually a problem and is intended. I double checked with jgriffith (Cinder PTL) and he agrees.