[lxc-users] User namespaces

[Serge Hallyn]

Quoting Fajar A. Nugraha (list at fajar.net):
> On Thu, Feb 26, 2015 at 5:48 AM, <david.andel at bli.uzh.ch> wrote:
> >
> > Hi,
> >
> > I am looking into individual user namespaces for each container.
> > The first container could have uids and gids from 100000 to 165536.
> > The second container could have 200000 to 265536, couldn't it?
> > How far can I go? Is there a limit?
> 
> From Google: http://serverfault.com/questions/105260/how-big-in-bits-is-a-unix-uid
> 
> On my system (64-bit ubuntu) it's 2^32 - 2
> 
> # touch /tmp/test
> 
> # chown 4294967294 /tmp/test
> 
> # ls -la /tmp/test
> -rw-r--r-- 1 4294967294 root 0 Mar 11 16:45 /tmp/test
> 
> # chown 4294967295 /tmp/test
> chown: invalid user: ‘4294967295’

fwiw you can also cat /proc/self/uid_map on the host to
see the full range.

         0          0 4294967295