Comment 1 for bug 1807044

Another thing that is probably contributing to the slow nova-api start time is that every nova.compute.api.API constructs a SchedulerReportClient, which grabs an in-memory lock per API worker during init:

Dec 05 20:14:27.694593 ubuntu-xenial-ovh-bhs1-0000959981 <email address hidden>[23459]: DEBUG oslo_concurrency.lockutils [None req-dfdfad07-2ff4-43ed-9f67-2acd59687e0c None None] Lock "placement_client" released by "nova.scheduler.client.report._create_client" :: held 0.006s {{(pid=23462) inner /usr/local/lib/python2.7/dist-packages/oslo_concurrency/lockutils.py:339}}

We could probably be smarter about either making that a singleton in the API or only init on first access since most of the API extensions aren't going to even use that SchedulerReportClient.