similar condition on my node.
The hypervisor id=1 is not KVM.

nicira@htb-1n-eng-dhcp8:/opt/stack/logs$ nova hypervisor-list
+----+------------------------------------------------+-------+---------+
| ID | Hypervisor hostname                            | State | Status  |
+----+------------------------------------------------+-------+---------+
| 1  | domain-c8.54363740-b6b7-42b4-b007-c1649977cd50 | up    | enabled |
| 2  | kvm-compute-node1                              | up    | enabled |
+----+------------------------------------------------+-------+---------+
nicira@htb-1n-eng-dhcp8:/opt/stack/logs$ nova hypervisor-show 1
ERROR (ClientException): Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<type 'exceptions.ValueError'> (HTTP 500) (Request-ID: req-e091d6bb-93e1-43d8-866d-8be6c037540e)
nicira@htb-1n-eng-dhcp8:/opt/stack/logs$ nova hypervisor-show 2
+---------------------------+----------------------------------------+
| Property                  | Value                                  |
+---------------------------+----------------------------------------+
| cpu_info_arch             | x86_64                                 |
| cpu_info_features         | ["pge", "clflush", "sep", "syscall",   |
|                           | "vme", "msr", "vmx", "cmov", "fpu",    |
|                           | "pat", "lm", "tsc", "nx", "fxsr",      |
|                           | "sse4.1", "pae", "sse4.2", "pclmuldq", |
|                           | "mmx", "cx8", "mce", "de", "rdtscp",   |
|                           | "mca", "pse", "pni", "popcnt", "apic", |
|                           | "sse", "ds", "lahf_lm", "aes", "sse2", |
|                           | "ss", "hypervisor", "ssse3", "cx16",   |
|                           | "pse36", "mtrr"]                       |
| cpu_info_model            | Westmere                               |
| cpu_info_topology_cells   | 1                                      |
| cpu_info_topology_cores   | 1                                      |
| cpu_info_topology_sockets | 8                                      |
| cpu_info_topology_threads | 1                                      |
| cpu_info_vendor           | Intel                                  |
| current_workload          | 0                                      |
| disk_available_least      | 8                                      |
| free_disk_gb              | 14                                     |
| free_ram_mb               | 15536                                  |
| host_ip                   | 10.144.139.89                          |
| hypervisor_hostname       | kvm-compute-node1                      |
| hypervisor_type           | QEMU                                   |
| hypervisor_version        | 2000000                                |
| id                        | 2                                      |
| local_gb                  | 14                                     |
| local_gb_used             | 0                                      |
| memory_mb                 | 16048                                  |
| memory_mb_used            | 512                                    |
| running_vms               | 0                                      |
| service_disabled_reason   | None                                   |
| service_host              | kvm-compute-node1                      |
| service_id                | 9                                      |
| state                     | up                                     |
| status                    | enabled                                |
| vcpus                     | 8                                      |
| vcpus_used                | 0                                      |
+---------------------------+----------------------------------------+
nicira@htb-1n-eng-dhcp8:/opt/stack/logs$ 


### n-api.log:
#################
2016-07-25 02:51:47.404 DEBUG nova.osapi_compute.wsgi.server [req-3967381d-706b-49a3-9dc8-57f7b9bfc608 None None] (32039) accepted ('10.144.138.49', 46862) from (pid=32039) server /usr/local/lib/python2.7/dist-packages/eventlet/wsgi.py:868
2016-07-25 02:51:47.528 INFO nova.osapi_compute.wsgi.server [req-da2665a6-38ca-42a1-bb19-1f16a45aa90e admin admin] 10.144.138.49 "GET /v2.1 HTTP/1.1" status: 302 len: 249 time: 0.1223969
2016-07-25 02:51:47.614 DEBUG nova.api.openstack.wsgi [req-d812ed1d-3567-4733-b2ac-bbc922cf118e admin admin] Calling method '<bound method VersionsController.show of <nova.api.openstack.compute.versionsV21.VersionsController object at 0x7f96c40e3f90>>' from (pid=32039) _process_stack /opt/stack/nova/nova/api/openstack/wsgi.py:636
2016-07-25 02:51:47.617 INFO nova.osapi_compute.wsgi.server [req-d812ed1d-3567-4733-b2ac-bbc922cf118e admin admin] 10.144.138.49 "GET /v2.1/ HTTP/1.1" status: 200 len: 720 time: 0.0844119
2016-07-25 02:51:47.889 DEBUG nova.api.openstack.wsgi [req-2bc1bb74-775f-4891-98f9-18b614638d04 admin admin] Calling method '<bound method HypervisorsController.show of <nova.api.openstack.compute.hypervisors.HypervisorsController object at 0x7f96c4539450>>' from (pid=32039) _process_stack /opt/stack/nova/nova/api/openstack/wsgi.py:636
2016-07-25 02:51:47.919 ERROR nova.api.openstack.extensions [req-2bc1bb74-775f-4891-98f9-18b614638d04 admin admin] Unexpected exception in API method
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions Traceback (most recent call last):
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/extensions.py", line 338, in wrapped
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions     return f(*args, **kwargs)
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/compute/hypervisors.py", line 170, in show
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions     hyp, service, True, req))
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions   File "/opt/stack/nova/nova/api/openstack/compute/hypervisors.py", line 72, in _view_hypervisor
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions     hyp_dict['cpu_info'] = jsonutils.loads(hypervisor.cpu_info)
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions   File "/usr/local/lib/python2.7/dist-packages/oslo_serialization/jsonutils.py", line 235, in loads
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions     return json.loads(encodeutils.safe_decode(s, encoding), **kwargs)
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions   File "/usr/lib/python2.7/json/__init__.py", line 338, in loads
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions     return _default_decoder.decode(s)
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions   File "/usr/lib/python2.7/json/decoder.py", line 366, in decode
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions   File "/usr/lib/python2.7/json/decoder.py", line 384, in raw_decode
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions     raise ValueError("No JSON object could be decoded")
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions ValueError: No JSON object could be decoded
2016-07-25 02:51:47.919 TRACE nova.api.openstack.extensions 
2016-07-25 02:51:47.921 INFO nova.api.openstack.wsgi [req-2bc1bb74-775f-4891-98f9-18b614638d04 admin admin] HTTP exception thrown: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<type 'exceptions.ValueError'>
2016-07-25 02:51:47.922 DEBUG nova.api.openstack.wsgi [req-2bc1bb74-775f-4891-98f9-18b614638d04 admin admin] Returning 500 to user: Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.
<type 'exceptions.ValueError'> from (pid=32039) __call__ /opt/stack/nova/nova/api/openstack/wsgi.py:1044
2016-07-25 02:51:47.924 INFO nova.osapi_compute.wsgi.server [req-2bc1bb74-775f-4891-98f9-18b614638d04 admin admin] 10.144.138.49 "GET /v2.1/os-hypervisors/1 HTTP/1.1" status: 500 len: 563 time: 0.0685430