[218] in athena10
Re: Cluster machine reset idea
daemon@ATHENA.MIT.EDU (Matthew S Goldstein)
Wed May 28 22:09:29 2008
Date: Wed, 28 May 2008 22:08:44 -0400 (EDT)
From: Matthew S Goldstein <austein@MIT.EDU>
To: Kenneth Arnold <kcarnold@MIT.EDU>
cc: Timothy G Abbott <tabbott@MIT.EDU>, athena10@MIT.EDU
In-Reply-To: <483DF274.7090504@mit.edu>
Message-ID: <Pine.LNX.4.64L.0805282159530.5667@cheshire-cat.mit.edu>
MIME-Version: 1.0
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I had a similar idea recently for cluster machines.
However, instead of running the VMs locally, have the VM running on
servers elsewhere. The cluster machines will have a client which connects
to the VM, giving instant login. Once the client is connected, a live
migration starts of the VM to the cluster machine so any extended login
can take advantage of the local processing power.
I'm told VMWare can deal with the live migrations, but this scheme
requires there be servers constantly running the VMs/holding them readily
accessible.
--Matt
On Wed, 28 May 2008, Kenneth Arnold wrote:
> Here's an even more drastic idea:
>
> The cluster machines run virtual Athena 10 and WinAthena images side-by-side.
> (Ctrl-Alt-F1 for Linux, Ctrl-Alt-F2 for Windows). When you log off of either,
> they just return to a saved state. Software upgrades are then handled by
> rsyncing the hard disk image (clone, rsync, kill VM, replace old image, start
> VM).
>
> And dreaming even more... it would be cool if users could easily move a
> session from one computer to another. I think VMware does that on servers
> side, but I don't see an obvious solution on their site for doing it with
> desktops.
>
> The VMs could be VMware (they'd be happy, but I don't know if it has the
> interfaces we'd need -- basically a "reset-me-now" guest OS op) or something
> else; do cluster machines have hardware-assisted virtualization?
>
> I do like the LVM idea too; maybe Linux could run native with that. I think I
> even saw support for LVM snapshots in schroot, for whatever that means. Tim
> wins in simplicity.
>
> -Ken
>
>
> Timothy G Abbott wrote:
>> One problem that we will probably experience with running Debian-based
>> cluster machines is that users will su to root and then apt-get install
>> some packages containing programs that they want to run for that session.
>> The cluster maintainance code would then have to be responsible for
>> removing any such packages cleanly.
>>
>> I thought of the idea of having (most of) the filesystem tree that you see
>> when you login graphically be a chroot containing an LVM snapshot of the
>> actual Athena source filesystem, which is then destroyed when you log out.
>> Directories that want to survive past the user logging out, like /home,
>> /tmp, various parts of /var, etc. would be bind-mounted from the source
>> filesystem, and thus preserved when users log out.
>>
>> I would not intend this to be a security measure, but instead a mechanism
>> for making it difficult for users to accidentally reconfigure cluster
>> machines.
>>
>> I'm not convinced that this idea doesn't have serious problems, but some
>> variation on it might be a good way to support temporarily installing
>> software on cluster machines using apt.
>>
>> -Tim Abbott
>
>
