when running rally -v task start boot-and-delete.json, the task always fails and each iteration reports the following message:

ITER: 0 END: Error <class 'rally.exceptions.GetResourceErrorStatus'>: Resouce <Server: rally_novaserver_oqxmhtbpzzjwwfpo> has ERROR status: NoValidHost

I have checked that there are enough available resources(vCPU, RAM etc) in compute nodes. Boot and delete operations on Dashboard work okay.

I have also checked nova.conf file, rabbitmq configuration is correct. and here is scheduler setting:

##### SCHEDULER #####

compute_scheduler_driver=nova.scheduler.filter_scheduler.FilterScheduler
scheduler_available_filters=nova.scheduler.filters.all_filters
scheduler_default_filters=AvailabilityZoneFilter,RamFilter,ComputeFilter,CoreFilter,SameHostFilter,DifferentHostFilter
default_availability_zone=nova  
default_schedule_zone=nova  
storage_availability_zone=nova

Wonder how to fix this NoValidHost problem, can anybody give some advice? Thanks in advance!