[9fans] To virtualise cpu/fs/auth-servers, or not?

[9fans] To virtualise cpu/fs/auth-servers, or not?

[Jonas Amoson]

The plan9-way seems to be to divide the tasks
of running programs, storing files, authenti-
cation and user interaction, to separate
servers or computers. This makes sense in
a large system with many users, but does it
also have appeal in a system with at most a
couple of users (mostly me)?

How do you feel about using virtualisation
(e.g. using vmware) for splitting the plan9-
roles to different virtual machines?

One take is that it is the task of the OS
to handle different task securely and in
isolation, but that it might be good to add
layers, for the sake of robustness?

Up till now, I have been drawterming to
an all-in-one cpu/fs/auth-server. Nothing
very demanding, really. More out for a
philosophical discussion.

Jonas Amoson

Re: [9fans] To virtualise cpu/fs/auth-servers, or not?

[erik quanstrom]

> The plan9-way seems to be to divide the tasks
> of running programs, storing files, authenti-
> cation and user interaction, to separate
> servers or computers. This makes sense in
> a large system with many users, but does it
> also have appeal in a system with at most a
> couple of users (mostly me)?
>
[...]
>
> Up till now, I have been drawterming to
> an all-in-one cpu/fs/auth-server. Nothing
> very demanding, really. More out for a
> philosophical discussion.

i find it's very useful to seperate the fs from
everything else.  since i run ken's fs, i don't
have a choice.  even if i did, it's really a good
idea to not allow any of the problems devon's
pointing out (or normal bugs) torpedo your
fs.

with vms and fossil/venti, you may pay a performance
penalty for this.  i don't know.

- erik

Re: [9fans] To virtualise cpu/fs/auth-servers, or not?

[andrey mirtchovski]

i still like to think of private namespaces as the ultimate
virtualizer: your ns is your "virtual environment", the file server
you're mounting is the  "hypervisor". i don't care that it doesn't
simulate actual hardware like xen/qemu. after all, each has layers and
layers of abstractions to get you from the hardware to a usable
environment.

Re: [9fans] To virtualise cpu/fs/auth-servers, or not?

[erik quanstrom]

On Thu Apr 16 19:08:23 EDT 2009, mirtchovski@gmail.com wrote:
> i still like to think of private namespaces as the ultimate
> virtualizer: your ns is your "virtual environment", the file server
> you're mounting is the  "hypervisor". i don't care that it doesn't
> simulate actual hardware like xen/qemu. after all, each has layers and
> layers of abstractions to get you from the hardware to a usable
> environment.

it breaks down when you realize that some resources (processes, memory)
are not part of a namespace.

- erik

Re: [9fans] To virtualise cpu/fs/auth-servers, or not?

[andrey mirtchovski]

> it breaks down when you realize that some resources (processes, memory)
> are not part of a namespace.

neither are the VMs running on a single node (looked at from dom0, to
give the conventional Xen example). the effects of a process running
in one VM could still be felt in another, even if that process can't
be seen in a /proc on it. that 'ps' in plan9 can view every process on
a plan9 machine is simply a convenience bestowed upon us by its
creators.