we should not log unimplemented error in _get_host_metrics method

[Tao Li]

When nova used ironic driver， there was an exception which was always logged in nova compute log fie periodically. The update_available_resource method calls the _get_host_metrics method to cause this problem. In ironic driver , the get_host_cpu_stats method is not implemented. so we should not log the exception message to eliminate misunderstanding. The cycle logged message is as follows.

2017-03-20 14:14:43.669 10933 INFO nova.compute.resource_tracker [req-c4decc3b-f8b4-49c4-afba-40b6c70e86be - - - - -] Final resource view: name=20ba28a6-a00d-46e8-983e-c6ef4140cc21 phys_ram=0MB used_ram=0MB phys_disk=0GB used_disk=0GB total_vcpus=0 used_vcpus=0 pci_stats=[]
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver [req-c4decc3b-f8b4-49c4-afba-40b6c70e86be - - - - -] Not all properties needed are implemented in the compute driver
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver Traceback (most recent call last):
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver File "/usr/lib/python2.7/site-packages/nova/compute/monitors/cpu/virt_driver.py", line 59, in _update_data
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver stats = self.driver.get_host_cpu_stats()
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver File "/usr/lib/python2.7/site-packages/nova/virt/driver.py", line 1224, in get_host_cpu_stats
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver raise NotImplementedError()
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver NotImplementedError
2017-03-20 14:14:43.670 10933 ERROR nova.compute.monitors.cpu.virt_driver

So, I want to ignore the unimplemented excepion in the '_update_data' method in virt_driver.py.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/465797

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/465797
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=3c95e12d0c1d4a5bb8486cb4b25b37ee216c3b8b
Submitter: Jenkins
Branch: master

commit 3c95e12d0c1d4a5bb8486cb4b25b37ee216c3b8b
Author: Tao Li <[e-mail]>
Date: Thu May 18 11:51:11 2017 +0800

    Change log level from ERROR to DEBUG for NotImplemented

    The exception message should not be logged in file when some
    methods are not implemented.

    Closes-Bug: #1674257

    Change-Id: If5759272cd295448ad4c33de2c611706edc8f62f

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 16.0.0.0b2 development milestone.