突然想起个问题，ｌｉｎｕｘ系统里的ｎａｍｅｓｐａｃｅ到底有什么用？是为了解决什么问题？
从内核的层面构造出虚拟机？
比如ＩＰＣ，这个时候
https://lwn.net/Articles/531114/
这个链接中说涉及ｎａｍｅｓｐａｃｅ的总体的目的是为了实现虚拟机
https://lwn.net/Articles/524952/
这篇文章中说是为了解决：【上面文章好好读】
There are many use cases for hypervisors. One is simple resource isolation, so that, for example, one can run a web server and a mail server on the same physical machine without having them interfere with one another. Another use case is to gather accurate service statistics. Thus, for example, the system manager may want to run top in order to obtain statistics about the mail server without seeing the effect of a database server on the same physical machine; placing the two servers in separate virtual machines allows such independent statistics gathering.
Hypervisors can be useful in conjunction with network applications. Since each virtual machine has its own IP address and port number space, it is possible, for example, to run two different web servers that each use port 80 inside different virtual machines. Hypervisors can also be used to provide root privilege to a user on one particular virtual machine. That user can then do anything they want on that virtual machine, without any danger of damaging the host system.
Finally, hypervisors can be used to run different versions of Linux on the same system, or even to run different operating systems (e.g., Linux and Windows) on the same physical machine.
【人类社会资源问题】
User namespaces provide isolation of the "user ID" resource. Thus, it is possible to create users that are visible only within a container. Most notably, user namespaces allow a container to have a user that has root privileges for operations inside the container without being privileged on the system as a whole. (There are various other namespaces in addition to those that Glauber discussed, such as the PID, UTS, and IPC namespaces. One or two of those namespaces were also mentioned later in the talk.)
