[EMAIL PROTECTED] (Herbert Poetzl) writes:

>> > > Using this new system call, chmod 000 is not needed anymore
>> > > and we can support vservers inside vservers.
>> > why don`t use private namespace ?
>> 
>> How does it work ?
>
> you should join a discussion with Enrico and me on IRC
> .. basically it is based on CLONE_NEWNS() and relatives ...

IMO, it is not doable with current technology:

* CLONE_NEWNS has strange behavior[1]; this will be fixed[2] in
  2.4.23 probably

* CLONE_NEWNS + pivot_root are requiring CAP_SYS_ADMIN (which
  is not acceptably for vservers); using a new capability for
  CLONE_NEWNS seems to be possible, but pivot_root(2) needs
  additional logic. Else, when executed in root-namespace,
  pivot_root(2) can do really bad things with your system.

* joining foreign namespaces (e.g. for 'vserver ... enter') is
  not implemented in current kernel; I saw patches but AFAIS,
  they are missing important logic (e.g. no capability-check).
  This functionality will need hierarchical contextes also
  (e.g. parent-vserver can enter namespace of child-vservers,
  but not this of if siblings or parents).




Enrico

Footnotes: 
[1]  http://www.tu-chemnitz.de/~ensc/nst.c

[2]  http://linux.bkbits.net:8080/linux-2.4/diffs/fs/[EMAIL PROTECTED]|[EMAIL 
PROTECTED]|[EMAIL PROTECTED]|hist/fs/namespace.c

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