oenstack nova 源码分析

1.创建虚拟机

def create(self, req, body):
"""Creates a new server for a given user."""

context = req.environ['nova.context']
server_dict = body['server']
password = self._get_server_admin_password(server_dict)
name = common.normalize_name(server_dict['name'])

if api_version_request.is_supported(req, min_version='2.19'):
if 'description' in server_dict:
# This is allowed to be None
description = server_dict['description']
else:
# No default description
description = None
else:
description = name

# Arguments to be passed to instance create function
create_kwargs = {}

# Query extensions which want to manipulate the keyword
# arguments.
# NOTE(cyeoh): This is the hook that extensions use
# to replace the extension specific code below.
# When the extensions are ported this will also result
# in some convenience function from this class being
# moved to the extension
if list(self.create_extension_manager):
self.create_extension_manager.map(self._create_extension_point,
server_dict, create_kwargs, body)

availability_zone = create_kwargs.pop("availability_zone", None)

<span style="white-space:pre"> </span># 将<span style="white-space:pre"> </span><span style="font-family: Arial, Helvetica, sans-serif;">server_dict 里的一些参数转入</span><span style="font-family: Arial, Helvetica, sans-serif;">create_kwargs中，还涉及到注入文件</span>

<span style="white-space:pre">	</span>helpers.translate_attributes(helpers.CREATE,
server_dict, create_kwargs)

target = {
'project_id': context.project_id,
'user_id': context.user_id,
'availability_zone': availability_zone}

<span style="white-space:pre">	</span># can 是？
context.can(server_policies.SERVERS % 'create', target)

# TODO(Shao He, Feng) move this policy check to os-availability-zone
# extension after refactor it.
parse_az = self.compute_api.parse_availability_zone
try:
availability_zone, host, node = parse_az(context,
availability_zone)
except exception.InvalidInput as err:
raise exc.HTTPBadRequest(explanation=six.text_type(err))
if host or node:
context.can(server_policies.SERVERS % 'create:forced_host', {})

min_compute_version = objects.Service.get_minimum_version(
nova_context.get_admin_context(), 'nova-compute')
supports_device_tagging = (min_compute_version >=
DEVICE_TAGGING_MIN_COMPUTE_VERSION)

block_device_mapping = create_kwargs.get("block_device_mapping")
# TODO(Shao He, Feng) move this policy check to os-block-device-mapping
# extension after refactor it.
if block_device_mapping:
context.can(server_policies.SERVERS % 'create:attach_volume',
target)
for bdm in block_device_mapping:
if bdm.get('tag', None) and not supports_device_tagging:
msg = _('Block device tags are not yet supported.')
raise exc.HTTPBadRequest(explanation=msg)

<span style="white-space:pre">	</span>#<span style="font-family: Arial, Helvetica, sans-serif;">image_uuid </span><span style="font-family: Arial, Helvetica, sans-serif;"> </span>
image_uuid = self._image_from_req_data(server_dict, create_kwargs)

# NOTE(cyeoh): Although an extension can set
# return_reservation_id in order to request that a reservation
# id be returned to the client instead of the newly created
# instance information we do not want to pass this parameter
# to the compute create call which always returns both. We use
# this flag after the instance create call to determine what
# to return to the client
return_reservation_id = create_kwargs.pop('return_reservation_id',
False)

requested_networks = None
if ('os-networks' in self.extension_info.get_extensions()
or utils.is_neutron()):
requested_networks = server_dict.get('networks')

if requested_networks is not None:
requested_networks = self._get_requested_networks(
requested_networks, supports_device_tagging)

if requested_networks and len(requested_networks):
context.can(server_policies.SERVERS % 'create:attach_network',
target)

try:
<strong>flavor_id</strong> = self._flavor_id_from_req_data(body)
except ValueError:
msg = _("Invalid flavorRef provided.")
raise exc.HTTPBadRequest(explanation=msg)

try:
inst_type = flavors.get_flavor_by_flavor_id(
flavor_id, ctxt=context, read_deleted="no")
<span style="white-space:pre">	</span>    # 调用compute组件的api.py
(instances, resv_id) = <strong><em>self.compute_api.create</em></strong>(context,
inst_type,
image_uuid,
display_name=name,
display_description=description,
availability_zone=availability_zone,
forced_host=host, forced_node=node,
metadata=server_dict.get('metadata', {}),
admin_password=password,
requested_networks=requested_networks,
check_server_group_quota=True,
**create_kwargs)
except ..........
<span style="white-space:pre">	</span>.......
# If the caller wanted a reservation_id, return it
if return_reservation_id:
# NOTE(cyeoh): In v3 reservation_id was wrapped in
# servers_reservation but this is reverted for V2 API
# compatibility. In the long term with the tasks API we
# will probably just drop the concept of reservation_id
return wsgi.ResponseObject({'reservation_id': resv_id})

req.cache_db_instances(instances)
server = self._view_builder.create(req, instances[0])

if CONF.enable_instance_password:
server['server']['adminPass'] = password

robj = wsgi.ResponseObject(server)

return self._add_location(robj)