[PATCH 05/10] Core checkpoint/restart support code
Nathan Lynch
ntl at pobox.com
Mon Apr 4 08:40:08 PDT 2011
On Mon, 2011-04-04 at 10:10 -0500, Serge E. Hallyn wrote:
> Quoting Nathan Lynch (ntl at pobox.com):
> > On Sun, 2011-04-03 at 14:03 -0500, Serge E. Hallyn wrote:
> > > Quoting ntl at pobox.com (ntl at pobox.com):
> > > > Only a pid namespace init task - the child process produced by a call
> > > > to clone(2) with CLONE_NEWPID - is allowed to call these. The state
> > >
> > > So you make this useful for your cases by only using this with
> > > application containers - created using lxc-execute, or, more precisely,
> > > using lxc-init as the container's init. So a container running a stock
> > > distro can't be checkpointed.
> >
> > Correct, a conventional distro init won't work, and application
> > containers are my focus for now, at least.
> >
> >
> > > Is this just to keep the patch simple for now, or is there some reason
> > > to keep this limitation in place?
> >
> > I guess you're asking whether non-pid-init processes could be allowed to
> > use the syscalls?
>
> No. I'm asking whether you are intending to later on change the checkpoint
> API to allow an external task to checkpoint a pid-init process, rather than
> the pid-init process having to initiate it itself.
No, that is not the intention. I can see how that would be problematic
for those wanting to run minimally-modified distro containers, but I
think running a patched pid-init is a reasonable tradeoff to ask users
to make in order to get c/r. And there's nothing to keep the standard
distro inits from growing c/r capability.
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