CRIU
checkpoint/restore in userspace
CRIU可以保持一个进程的状态到文件，然后在另一台机器恢复运行。实现进程的热迁移。
criu is a tool for checkpointing and restoring running applications. It does this by saving their state as a collection of files (see the dump command) and creating
equivalent processes from those files (see the restore command). The restore operation can be performed at a later time, on a different system, or both.