Error log when running dibbler client

2017-03-06 16:20:37.327 DEBUG neutron.agent.linux.dibbler [-] Enable IPv6 PD for router b59fb44c-b301-47bb-bc8e-e78e
30eb097e subnet 39acb4b5-4d5a-4d62-a295-b7c289d0a751 ri_ifname qr-0d51bc23-f6 from (pid=32154) enable /media/sf_Rack
space/neutron/neutron/agent/linux/dibbler.py:123
2017-03-06 16:20:37.327 DEBUG neutron.agent.linux.utils [-] Unable to access /opt/stack/data/neutron/pd/b59fb44c-b30
1-47bb-bc8e-e78e30eb097e:39acb4b5-4d5a-4d62-a295-b7c289d0a751:qr-0d51bc23-f6/client.pid from (pid=32154) get_value_f
rom_file /media/sf_Rackspace/neutron/neutron/agent/linux/utils.py:274
2017-03-06 16:20:37.329 DEBUG neutron.agent.linux.utils [-] Unable to access /opt/stack/data/neutron/pd/b59fb44c-b30
1-47bb-bc8e-e78e30eb097e:39acb4b5-4d5a-4d62-a295-b7c289d0a751:qr-0d51bc23-f6/client.pid from (pid=32154) get_value_f
rom_file /media/sf_Rackspace/neutron/neutron/agent/linux/utils.py:274
2017-03-06 16:20:37.330 DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ip', 'netns', 'exec
', 'snat-b59fb44c-b301-47bb-bc8e-e78e30eb097e', 'dibbler-client', 'start', '-w', '/opt/stack/data/neutron/pd/b59fb44
c-b301-47bb-bc8e-e78e30eb097e:39acb4b5-4d5a-4d62-a295-b7c289d0a751:qr-0d51bc23-f6'] from (pid=32154) execute_rootwra
p_daemon /media/sf_Rackspace/neutron/neutron/agent/linux/utils.py:113
2017-03-06 16:20:37.339 DEBUG oslo_concurrency.lockutils [-] Acquired semaphore "iptables-qrouter-b59fb44c-b301-47bb
-bc8e-e78e30eb097e" from (pid=32154) lock /usr/local/lib/python2.7/dist-packages/oslo_concurrency/lockutils.py:212
2017-03-06 16:20:37.340 DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ip', 'netns', 'exec
', 'qrouter-b59fb44c-b301-47bb-bc8e-e78e30eb097e', 'iptables-save'] from (pid=32154) execute_rootwrap_daemon /media/
sf_Rackspace/neutron/neutron/agent/linux/utils.py:113
2017-03-06 16:20:37.355 DEBUG neutron.agent.linux.utils [-] Exit code: 0 from (pid=32154) execute /media/sf_Rackspac
e/neutron/neutron/agent/linux/utils.py:154