os:centos 7.1 x86_64
network: nova-network
type :  kvm 

 +--------------------------------------+--------------+--------+------------+-------------+----------+
| ID                                   | Name         | Status | Task State | Power State | Networks |
+--------------------------------------+--------------+--------+------------+-------------+----------+
| f9b97c26-b516-45fa-897f-2ce2c3265a18 | hk-instance1 | ERROR  | -          | NOSTATE     |          |
| 994f7379-3d88-44d1-bb10-74fc3afc9a3c | hk-instance2 | ERROR  | -          | NOSTATE     |          |
+--------------------------------------+--------------+--------+------------+-------------+----------+

/var/log/nova/nova-conductor.log
2015-09-06 15:21:01.121 26778 WARNING nova.scheduler.utils [req-e20723cf-6361-441f-99ca-7ec3c92e483
c 000793204f2e411b8ec6d7efc4ab653d 02cf5d032c63420fa6fd84657482d387 - - -] Failed to compute_task_b
uild_instances: No valid host was found. There are not enough hosts available.
Traceback (most recent call last):

 nova service-list
+----+------------------+------------+----------+---------+-------+----------------------------+-----------------+
| Id | Binary           | Host       | Zone     | Status  | State | Updated_at                 | Disabled Reason |
+----+------------------+------------+----------+---------+-------+----------------------------+-----------------+
| 1  | nova-cert        | controller | internal | enabled | up    | 2015-09-06T07:37:30.000000 | -               |
| 2  | nova-consoleauth | controller | internal | enabled | up    | 2015-09-06T07:37:30.000000 | -               |
| 3  | nova-conductor   | controller | internal | enabled | up    | 2015-09-06T07:37:31.000000 | -               |
| 4  | nova-scheduler   | controller | internal | enabled | up    | 2015-09-06T07:37:32.000000 | -               |
+----+------------------+------------+----------+---------+-------+----------------------------+-----------------+

nova host-list
+------------+-------------+----------+
| host_name  | service     | zone     |
+------------+-------------+----------+
| controller | cert        | internal |
| controller | consoleauth | internal |
| controller | conductor   | internal |
| controller | scheduler   | internal |
+------------+-------------+----------+

nova hypervisor-list
+----+---------------------+-------+--------+
| ID | Hypervisor hostname | State | Status |
+----+---------------------+-------+--------+
+----+---------------------+-------+--------+

nova image-list
+--------------------------------------+---------------------+--------+--------+
| ID                                   | Name                | Status | Server |
+--------------------------------------+---------------------+--------+--------+
| c3a43454-b474-4acc-9cd3-7ebd7b8053f2 | cirros-0.3.4-x86_64 | ACTIVE |        |
+--------------------------------------+---------------------+--------+--------+

nova flavor-list
+----+-----------+-----------+------+-----------+------+-------+-------------+-----------+
| ID | Name      | Memory_MB | Disk | Ephemeral | Swap | VCPUs | RXTX_Factor | Is_Public |
+----+-----------+-----------+------+-----------+------+-------+-------------+-----------+
| 1  | m1.tiny   | 512       | 1    | 0         |      | 1     | 1.0         | True      |
| 2  | m1.small  | 2048      | 20   | 0         |      | 1     | 1.0         | True      |
| 3  | m1.medium | 4096      | 40   | 0         |      | 2     | 1.0         | True      |
| 4  | m1.large  | 8192      | 80   | 0         |      | 4     | 1.0         | True      |
| 5  | m1.xlarge | 16384     | 160  | 0         |      | 8     | 1.0         | True      |
+----+-----------+-----------+------+-----------+------+-------+-------------+-----------+

how should i do next?