问题
I have found, that Docker daemon runs more than in one instance. I have got PID(13399) with service docker status, but there are also different PIDs. I have created only one container.
回答1:
As you can see in the list the stats are basically the same (MEM, etc.). These processes are actually just forks from the original process.
Forking is usually used to execute another application in the environment of the parent process (in this case: docker). I don't know what docker specifically uses it for, there are many possibilities.
Some more information on the topic forking.
来源：https://stackoverflow.com/questions/33420700/docker-daemon-processes