Re: (pspace,pid) vs true pid virtualization

[Kirill Korotaev]

> > fine, agreed on this finally, same for OpenVZ.
> hey we have soemthing :)
:)

> > > definitely, we (Linux-VServer) added this some time ago
> > > and it helps to maintain/restart a guest.
> > but why sys_waitpid? we can make it in many other ways,
>
> yes, we currently have a syscall switch command 
> to wait for the guest, but, of course, it is
> very similar to the 'normal' unix waitpid()
this is more logically clean to me, since containers/namespaces are not 
tasks.
If someone wants to use more unix-like semantics, he can obtain fd for 
namespace and call select/poll on it :))))

> > And we had issues in OpenVZ, that very fast VPS stop/start can fail due 
> > to not freed resources yet.
> this is a design problem, if your design allows
> to have _more_ than one pid space with the same
> identifier/properties, but with only one active
> and thus reachable space, it is no problem to 
> create a new one right after the old one did send
> the event (which doesn't mean that it was destroyed
> just that the last process left the space)
see my another email about sockets.

> > How about third party apps?
> I don't think we care about third party apps when
> adding new kernel functionality, especially not
> proprietary ones which cannot be modified easily
Even if we don't take into account proprietary apps, there too many 
opensource control panels, management tools etc.
So this doesn't look good to me anyhow.

> > agreed. Though I don't like a backdoor name :) 
> > It is just a way to get access to VPS.

> well, it is often a way to get access to the VPS
> without the 'owner' of that VPS even knowing, so
> IMHO it's a backdoor, access would be via sshd or
> console :)
When you have a physical box there are many ways to get access to it 
without knowing passwords etc. This is the same.

Kirill

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