Re: guix on nfs based systems

[Efraim Flashner]

On Thu, Nov 23, 2023 at 09:41:56AM +0000, Etienne B. Roesch wrote:
> 
> On Thu, Nov 23, 2023 at 6:32 AM Efraim Flashner <efraim@flashner.co.il>
> wrote:
> 
> > On Wed, Nov 22, 2023 at 05:32:07PM +0000, Etienne B. Roesch wrote:
> > > Hi,
> > >
> > > I have been successful in convincing our IT dept to provide guix as
> > > standard on our vms and research clusters. We use this sophisticated
> > > platform that allows users to spawn a vm at will, and also use this
> > shared
> > > ldap user database to allow for people to log on from computers/terminals
> > > spread on campus. Home directories are basically pulled from the OS
> > (mostly
> > > ubuntu and centos) as a shared file system on the network, which then
> > > synchronises changes live. Practically, that means a user will find its
> > > desktop, preferences and files as they move to different computers.
> > >
> > > Theoretically, a user can connect to several computers at the same time,
> > > which can lead to conflict issues at times, e.g. firefox doesn't like
> > > parallel access to its preferences. I haven't fully tested it, but we
> > think
> > > that a guix profile is specific to a given computer, because of the way
> > it
> > > links to the store, which is (currently) local to the vm, which isn't
> > > ideal: the whole point of using vms is for users to kill them when they
> > > don't need them.
> > >
> > > What would be the recommended way of solving this? Has anybody had a
> > > similar situation?
> > > I am thinking we could either:
> > > - leave it as is, and train users to recreate their profiles whenever
> > they
> > > use a new vm/computer (after all, that's what guix is for) but it could
> > > take some time to recompile if binaries aren't available
> > > - maybe turn /gnu/store as a shared nfs folder
> >
> > CCing guix-science
> >
> > One thing we do on the small cluster at UTenn is /gnu and /var/guix (in
> > addition to the home directories) are exported across NFS and then any
> > profiles that are installed in the users' home directories have their
> > symlinks not dangling.
> >
> > I also have a snippet in my .profile to use GUIX_DAEMON_SOCKET to ssh
> > back to the head node to use the guix-daemon there, which keeps all the
> > guix stuff on one machine and easier to manage and make sure the same
> > software is available on all the machines.
> >
> Thanks! That's really helpful! How robust is your system to bandwidth
> fluctuations and network hiccups?
> How big is your store, /gnu, /var/guix?
> 
> How many users do you have?
> 
> Etienne

We have about a dozen users, with about 100GB for /gnu. It'd probably be
better with a larger store, but that's what we've partitioned for it.
/var/guix is rather small and not really worth worrying about.

We started with gigabit ethernet which seems to be fast enough for
accessing files from /gnu/store but could be faster when it comes to the
shared storage so we have a local scratch SSD on each system for local
files while doing computations.

-- 
Efraim Flashner   <efraim@flashner.co.il>   רנשלפ םירפא
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