How was the container created and how does it work

问题:

First of all thank you for your answer, whether it is useful or not. I don't quite understand Container, the problem is as follows

1. Is Contatiner a component of NodeManager?
2. Is the Contatiner created with NodeManager?
3. When NodeManager or MRAppMaster wants to start a Contatiner, do you only need to configure it?
4. Is there a collection of available resources in the scheduler? Will some resources be allocated for running jobs every time? Is it like cutting a ham?
5. I want to know how a Contatiner is started or created in ResourceManager.

I hope the answer can be simpler and easier to understand, and it is best to have a picture show. Thank you.