Re: [PATCH 1/7] ns: proc files for namespace naming policy.

From: Daniel Lezcano
Date: Sat May 07 2011 - 18:38:29 EST


On 05/07/2011 04:24 AM, Eric W. Biederman wrote:
Create files under /proc/<pid>/ns/ to allow controlling the
namespaces of a process.

This addresses three specific problems that can make namespaces hard to
work with.
- Namespaces require a dedicated process to pin them in memory.
- It is not possible to use a namespace unless you are the child
of the original creator.
- Namespaces don't have names that userspace can use to talk about
them.

The namespace files under /proc/<pid>/ns/ can be opened and the
file descriptor can be used to talk about a specific namespace, and
to keep the specified namespace alive.

A namespace can be kept alive by either holding the file descriptor
open or bind mounting the file someplace else. aka:
mount --bind /proc/self/ns/net /some/filesystem/path
mount --bind /proc/self/fd/<N> /some/filesystem/path

This allows namespaces to be named with userspace policy.

It requires additional support to make use of these filedescriptors
and that will be comming in the following patches.

Signed-off-by: Eric W. Biederman<ebiederm@xxxxxxxxxxxx>
Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxx>

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