nova-api performance issues on "openstack server list"

[David Moreau Simard]

Relevant information TL;DR:
RDO stable Mitaka deployed with OpenStack puppet modules.
Keystone with fernet tokens, Nova with keystone_authtoken memcached caching set (also reproduced with sql tokens and nova without memcached caching for authtoken). nova-api is handled behind apache with mod wsgi.

Problem TL;DR:
In an empty new deployment on bare metal (no images, no virtual machines, etc.), "openstack server list" will intermittently take >5 seconds (up to ~10) to return. The only noticeable thing that happens when "openstack server list" is slow is that the logs will be plastered with a bunch of "_create_extension_schema", "_rebuild_extension_schema", "_register_resources" and so on.
All other installed projects (glance, keystone, neutron) return command output consistently under 2 seconds.

Version info:
# rpm -qa |grep nova
openstack-nova-api-13.0.0-1.el7.noarch
python-novaclient-3.3.0-1.el7.noarch
openstack-nova-scheduler-13.0.0-1.el7.noarch
python-nova-13.0.0-1.el7.noarch
openstack-nova-conductor-13.0.0-1.el7.noarch
openstack-nova-common-13.0.0-1.el7.noarch

/etc/nova/nova.conf: http://paste.fedoraproject.org/367251/34295211/raw/

Example log of when things are fast: http://paste.fedoraproject.org/367272/32783146/raw/
Example log of when things are slow: http://paste.fedoraproject.org/367271/34327341/raw/

Happy to help provider further details if required.

[David Moreau Simard (dmsimard)]

Oddly enough, after a while I am no longer able to reproduce the issue. There may be some sort of warm up period of sorts.

[Andrea Rosa (andrea-rosa-m)]

based on your last comment I am going to close this bug as it is not "reproducible".
Please feel free to re-open it if you have a clear way to reproduce it again.
Thanks