openstack.nova.manager创建虚拟机流程(run_instance)

xxqyzsc

　　上面的代码整理自 nova/compute/manager.py 代码的顺序有改动，只是为了方便查看，完整的代码可以参考：https://github.com/openstack/nova/blob /master/nova/compute/manager.py
　　虚拟机的创建流程为3步走：

• 向nova-network申请IP
  
• 向nova-volumn申请block_device
  
• 向driver申请创建虚拟机
  

　　同时伴随整个过程，虚拟机的vm_state始终是building，但是task_state将会变化三次：

• networking
  
• block_device_mapping
  
• spawing
  

　　最后，虚拟机的vm_state变成active.



def run_instance(self):

building proccess:
None
+
networking
|  network_api.allocate_for_instance (nova-network)
+
block_device_mapping
|  setup_block_device_mapping (nova-volumn)
+
spawing
|  driver.spawn (nova-compute.driver)
+
Active
"""
instance = self.db.instance_get_by_uuid(context, instance_uuid)
self._check_instance_not_already_created(context, instance)
image_meta = self._check_image_size(context, instance)
# VM_state = building
# task_state = None
self._instance_update(context, instance['uuid'],
host=self.host, launched_on=self.host,
vm_state=vm_states.BUILDING,
task_state=None)
# VM_state = building
# task_state = networking
self._instance_update(context, instance['uuid'],
vm_state=vm_states.BUILDING,
task_state=task_states.NETWORKING)
network_info = self.network_api.allocate_for_instance(
context, instance, vpn=is_vpn,
requested_networks=requested_networks)

# VM_state = building
# task_statue = block_device_mapping
self._instance_update(context, instance['uuid'],
vm_state=vm_states.BUILDING,
task_state=task_states.BLOCK_DEVICE_MAPPING)
self._setup_block_device_mapping(context, instance)

# VM_state = building
# task_statue = spawing
self._instance_update(context, instance['uuid'],
vm_state=vm_states.BUILDING,
task_state=task_states.SPAWNING)
instance['injected_files'] = injected_files
instance['admin_pass'] = admin_pass
self.driver.spawn(context, instance, image_meta,
self._legacy_nw_info(network_info), block_device_info)
# VM_state = active
# task_statue = None
self._instance_update(context, instance['uuid'],
power_state=current_power_state,
vm_state=vm_states.ACTIVE,
task_state=None,
launched_at=utils.utcnow())