nova.scheduler.client.report 409 Conflict

[Serguei Bezverkhi]

With stable/newton and placement-api an instance fails to start.

Compute logs shows this error:

2017-03-11 04:20:58.830 7 DEBUG nova.scheduler.client.report [req-330e1b63-286f-47f4-b8ca-49365d9509b5 - - - - -] [instance: 4a33b8fc-b9a4-49ea-8afc-4cb15bd3f841] Sending allocation for instance {'allocations': [{'resource_provider': {'uuid': '610ee875-405e-4738-8099-5a218fa4986f'}, 'resources': {'MEMORY_MB': 512, 'VCPU': 1, 'DISK_GB': 1}}]} _allocate_for_instance /var/lib/kolla/venv/local/lib/python2.7/site-packages/nova/scheduler/client/report.py:397
2017-03-11 04:20:58.863 7 WARNING nova.scheduler.client.report [req-330e1b63-286f-47f4-b8ca-49365d9509b5 - - - - -] Unable to submit allocation for instance 4a33b8fc-b9a4-49ea-8afc-4cb15bd3f841 (409 409 Conflict

There was a conflict when trying to complete your request.

 Unable to allocate inventory: Unable to create allocation for 'MEMORY_MB' on resource provider '610ee875-405e-4738-8099-5a218fa4986f'. The requested amount would violate inventory constraints. )

Corresponding to this event placement-api log show this:

2017-03-11 04:20:58.857 15 WARNING nova.objects.resource_provider [req-a56a49ea-eda8-4e37-b87e-cffffd26e9e1 - - - - -] Allocation for MEMORY_MB on resource provider 610ee875-405e-4738-8099-5a218fa4986f violates min_unit, max_unit, or step_size. Requested: 512, min_unit: 1, max_unit: 1, step_size: 1
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation [req-a56a49ea-eda8-4e37-b87e-cffffd26e9e1 - - - - -] Bad inventory
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation Traceback (most recent call last):
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation File "/var/lib/kolla/venv/local/lib/python2.7/site-packages/nova/api/openstack/placement/handlers/allocation.py", line 253, in set_allocations
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation allocations.create_all()
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation File "/var/lib/kolla/venv/local/lib/python2.7/site-packages/nova/objects/resource_provider.py", line 1184, in create_all
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation self._set_allocations(self._context, self.objects)
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation File "/var/lib/kolla/venv/local/lib/python2.7/site-packages/oslo_db/sqlalchemy/enginefacade.py", line 894, in wrapper
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation return fn(*args, **kwargs)
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation File "/var/lib/kolla/venv/local/lib/python2.7/site-packages/nova/objects/resource_provider.py", line 1146, in _set_allocations
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation before_gens = _check_capacity_exceeded(conn, allocs)
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation File "/var/lib/kolla/venv/local/lib/python2.7/site-packages/nova/objects/resource_provider.py", line 1058, in _check_capacity_exceeded
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation resource_provider=rp_uuid)
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation InvalidAllocationConstraintsViolated: Unable to create allocation for 'MEMORY_MB' on resource provider '610ee875-405e-4738-8099-5a218fa4986f'. The requested amount would violate inventory constraints.
2017-03-11 04:20:58.858 15 ERROR nova.api.openstack.placement.handlers.allocation

[Andrey Volkov (avolkov)]

From description you provided it doesn't look like an error.

> Unable to create allocation for 'MEMORY_MB' on resource provider '610ee875-405e-4738-8099-5a218fa4986f'. The requested amount would violate inventory constraints.

means that on compute node you don't have enough memory resource.
You could look either at DB state (http://ix.io/oXq) or at placement API (http://ix.io/oXr)