ｎａｍｅｓｐａｃｅ做用是啥？

忽然想起個問題，ｌｉｎｕｘ系統裏的ｎａｍｅｓｐａｃｅ到底有什麼用？是爲了解決什麼問題？

從內核的層面構造出虛擬機？

好比ＩＰＣ，這個時候

https://lwn.net/Articles/531114/

這個連接中說涉及ｎａｍｅｓｐａｃｅ的整體的目的是爲了實現虛擬機

https://lwn.net/Articles/524952/

這篇文章中說是爲了解決：【上面文章好好讀】

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.

【人類社會資源問題】

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.)