- Assert: I don't understand about OPS/Redhat explaination. Because all of information said nova-conductor will help database-accessing for nova-compute, every chart/image showed, too.
From OPS Community
nova-conductor module: Mediates interactions between the nova-compute service and the database. It eliminates direct accesses to the cloud database made by the nova-compute service. The nova-conductor module scales horizontally. However, do not deploy it on nodes where the nova-compute service runs.
From Redhat
The nova-conductor service enables OpenStack to function without compute nodes accessing the database. Conceptually, it implements a new layer on top of nova-compute. It should not be deployed on compute nodes, or else the security benefits of removing database access from nova-compute are negated.
- Reality: When I download OPS Nova source code looked into nova/compute/manager.py, I saw the many many block code that queries the data from the database (instance list) and updates the data (instance.save).
def _poll_rescued_instances(self, context):
if CONF.rescue_timeout > 0:
filters = {'vm_state': vm_states.RESCUED,
'host': self.host}
rescued_instances = objects.InstanceList.get_by_filters(
context, filters, expected_attrs=["system_metadata"],
use_slave=True)
def _allocate_network(self, context, instance, requested_networks,
security_groups, resource_provider_mapping,
network_arqs):
"""Start network allocation asynchronously. Return an instance
of NetworkInfoAsyncWrapper that can be used to retrieve the
allocated networks when the operation has finished.
"""
# NOTE(comstud): Since we're allocating networks asynchronously,
# this task state has little meaning, as we won't be in this
# state for very long.
instance.vm_state = vm_states.BUILDING
instance.task_state = task_states.NETWORKING
instance.save(expected_task_state=[None])
So the assertion of the Openstack and Redhat development community is wrong or true????
