restart (mktree) program usage

[Serge E. Hallyn]

Quoting Oren Laadan (orenl at librato.com):
> 
> 
> Sukadev Bhattiprolu wrote:
> > Oren Laadan [orenl at librato.com] wrote:
> > | 
> > | 
> > | Sukadev Bhattiprolu wrote:
> > | > I have a usage question on the 'restart' (formerly mktree) program.
> > | > 
> > | > In the following container c/r case: 
> > | > 
> > | > 	- create a container
> > | > 	- log in to the container,
> > | > 	- restore filesystem(s) from snapshot
> > | > 	- restart application from checkpoint
> > | 
> > | FWIW, I'd expect that future versions of 'restart' will be capable
> > | of doing this entire setup, (filesystem(s) included), as it matures.
> > | 
> > | Note that this use case that you suggest will only work to restart
> > | subtrees; it is unsuitable for full containers (with pids) because
> > | the pid of init (1) will already be in use.
> > 
> > True. But if originally the application was started as:
> > 
> > 	Create container
> > 	Login to contaienr
> 
> Actually, I'm not sure what you mean by "login to container" ?

I assume he was thinking of a system container created with liblxc
or libvirt, and literally logging in on its console or over ssh.

...

> > Yes, that would be really useful I think for things like restoring file
> > system to its snapshot. Without that there is somewhat of an assymetry
> > in starting an application in a container and restarting it from a
> > checkpoint.

Fine, they are different operations :)

-serge