Re: [PATCH] [RFC] c/r: Add UTS support

[Daniel Lezcano <daniel.lezcano-GANU6spQydw@public.gmane.org>]

Dan Smith wrote:
> NL> I'd like there to be some discussion about this, because namespace
> NL> creation seems like a significant addition to the semantics of
> NL> restart as I understand it.
>
> Indeed.
>
> NL> Is namespace creation during restart unavoidable, or merely
> NL> desirable?  Is there a case for requiring the user to provide a
> NL> suitable namespace environment before attempting restart?
>
> Information about the namespaces has to be saved at checkpoint time no
> matter what, right?  I guess I don't see any compelling reason to not
> have the restart operation replicate the environment of the original
> process.  Otherwise we require userspace to read and interpret the
> checkpoint stream and selectively feed the bits that the kernel is
> responsible for to the kernel and process the rest itself (or have the
> kernel ignore those records).
>   

Assuming you have a process and this one unshared the network 100 times 
and each time opens a socket, how do you checkpoint these namespaces ?

> What's the argument for depending on userspace to set this up?
>   
Maybe, CR of the namespaces is more complicate topic than it looks like 
and the CR itself is big enough to not complicate things. IMHO, I would 
recommend as the first step to forbid the unshare inside a container and 
let the container implementation to save the configuration with the 
statefile in order to recreate it at the restart