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Comment by aidenn0 | Hacker News Reader

Is there an easy way to duplicate a specific process' namespace? My biggest issue with all these new features is that privatize state is how much harder it is to reproduce a state.

Back when it was just environment variables, I could pipe /proc/PID/environ to xargs and get basically the same state. Given that things like unix domain sockets may end up in $TMPDIR, I can be left unable to do certain things.

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    nsenter --all --target $PID

or something like that?

https://man7.org/linux/man-pages/man1/nsenter.1.html

/proc/PID/root is a view of that process’s mount namespace.

Also you can use nsenter(8) to run a command (or even a shell) under another process’s mount, pid, network, etc namespace.

Thanks!

It's exactly what I was looking for, and the world can now continue to improve without breaking any of my workflows :)

mount namespace and root directory are bit different things though.

/proc/$PID/ns is the place to look for namespaces

I don't think there is, or should be, a way to do that. Granular copying of per-process resource state seems like a need that would be better served at either a closer-to-the-program layer (i.e. debug hooks in code you control that provide information on how to reconstruct its state) or much further away (e.g. via CRIU/whole-machine snapshots or scary tricks like SIGSTP or ptrace-injecting calls to fork(2)).

> I can be left unable to do certain things

Most of what I can imagine of "certain things" falls into two categories: debugging (for which much better tools exist), or concerns that would be better served by a program providing an API of some kind rather than "go muck with state in $TMPDIR".

Here's a recent one; I needed to play some sound via an ssh login session. A Wayland/pipewire session was already open. I was able to do this just by copying a running processes environment. With enough containerization &c. I'll need to do more things to do that, if it's at all possible.

Also, /proc/ is (among other things) a debug interface.

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