From the Ocata upgrade notes:
Since the Placement service is now mandatory in Ocata, you need to deploy it and amend your compute node configuration with correct placement instructions before restarting nova-compute or the compute node will refuse to start.
- deploy puppet patch that installs and starts placement service
openstack service create --name placement --description "Placement API" placement
- add to keystone catalog (port 8778)
openstack endpoint create --region codfw1dev-r placement public http://openstack.codfw1dev.wikimediacloud.org:8778 openstack endpoint create --region codfw1dev-r placement internal http://openstack.codfw1dev.wikimediacloud.org:8778 openstack endpoint create --region codfw1dev-r placement admin http://openstack.codfw1dev.wikimediacloud.org:8778
- restart all nova-compute processes