On Mon, Oct 14, 2013 at 4:03 PM, David Leverton <[email protected]> wrote: > Rich Freeman wrote: >> >> However, FWIW, linux namespaces cannot be used to have only a single >> file appear differently to different processes. Mount namespaces can >> only operate at the directory level. > > > So to work around that limitation we insist that everyone change how their > systems are set up, and still have to reintroduce mtab under a different > name ("utab", hidden away under /run) because /proc/self/mounts *doesn't* > contain everything that's supposed to be in mtab after all? > > If someone decides they want to use, say, different DNS servers in different > namespaces, should we make the kernel store the server IP addresses, add a > /proc file that dumps them out in the expected format, and demand that > everyone replace their /etc/resolv.conf with a symlink to > /proc/self/resolv.conf? Or maybe, if people want namespaces, they can > implement them properly, in which case it becomes literally a self-solving > problem. > >
This is a horrible example. /etc/resolv.conf is a configuration file for code that lives entirely in userspace. Of course it makes no sense to shove that into the kernel.
