Re: “guix gc”, auto gcroots, cluster deployments

[Ricardo Wurmus]

Hi Roel,

> Maybe I'm making things needlessly complex, but I would really 
> like a
> solution that can be applied to an existing cluster setup. :)

Oh, I’d also like something automated that works for an existing 
cluster setup (like mine that prompted this conversation), but in 
my imagination this does not involve users running commands that 
would become part of the permanent Guix command line footprint.

Instead I imagine a sysadmin would have enough privileges to 
impersonate the users and rewrite the links for them.

Full automation is not possible in my case anyway, because I can’t 
necessarily tell who owns the target file (it’s not just user home 
directories but also some other obscurely named shared 
directories), nor can I figure out automatically on which server 
the link was created (when I see a link like “/local/foo/bar”, 
which is a server-local directory that is not exported on any 
other system).


Even though the two of us seem to agree that this change is 
necessary, it does result in a regression: for systems where none 
of this is a problem (e.g. single-user laptops) it’s rather 
inconvenient to have all these temporary gcroots accumulate. 
Prior to my proposed change they would be freed up for garbage 
collection as soon as the link was removed.

(I also wonder if the implementation of “guix gc 
--delete-generations” would need adjusting; I haven’t looked yet.)

Is there something we can do to have our cake and eat it too?

--
Ricardo