热迁移的时候提示WARNING nova.scheduler.utils [req-06dd66cf-7e67-491f-b84d-68699e87a026 bd43cf861cdc4fc7ac03bf104343968c 2150480345904b378d389571a75bdc1c] Failed to compute_task_migrate_server: Migration pre-check error: Unable to migrate c7f24ad4-9d33-4b43-941a-8fb9976c66e8 to network: Lack of memory(host:-12773 <= instance:8096)
即使虚拟机关闭了，还是提示内存不足。
解决办法：改代码吧
社区中的修改代码的方法:https://review.openstack.org/#/c/43213/2/nova/conductor/tasks/live_migrate.py
把下图中粉红色的代码去掉
