Re: mirari updates

[David Scott <scott.dj@xxxxxxxxx>]

On Tue, Mar 5, 2013 at 8:54 PM, Anil Madhavapeddy <anil@xxxxxxxxxx> wrote:

On 5 Mar 2013, at 17:56, Vincent Bernardoff <vb@xxxxxxxxxxxxxx> wrote:

> On 27/02/2013 21:52, Anil Madhavapeddy wrote:
>> - In the UNIX backend, in mirage-platform/unix/runtime/tap_stubs_*.c,
>>   we currently hardcode an `ifconfig 10.0.0.1` to give the tap device
>>   a static IP address.  This has made it easy so far to get networking
>>   up and running, but the tap device setup really ought to be done by
>>   Mirari-run instead of the Mirage-platform libraries (which should just
>>   open a tun passed to them).
>
> I don’t think mirari (and obviously even less Netif) should setup the tap since it requires root access. Mirari should give instructions on how to do so, but not issue root commands itself.

It doesn't necessarily need root: there are a bunch of platform-specific ways. For example, on Linux, you can set CAP_NET_ADMIN to the Mirari binary to gain access to tunctl.  There's a good summary of all the ways in the Erlang tuntap bindings here:

https://github.com/msantos/tunctl

(it might be worth creating a robust ocaml-tuntap that wraps these mechanisms)

An ocaml-tuntap package sounds like a very nice thing.

 

>
> About the Xen backend, we should decide on a standard way to execute kernels (as Anil said). At the moment, I only tested the xl create -c config.cfg kernel.xen method, which works well. If I understand well, it is better to use libvirt as it is a library that could be better integrated with mirari. I did not test it yet, but plan to do it asap.

Great. I know Dave has been experimenting with libvirt recently, but he's travelling this week.  Jon, Mike, do you have any opinions about this?

So far libvirt (via Richard Jones' ocaml bindings) is working well for me, although I've been focusing on the storage interface rather than the VM ("domain") interface. I haven't tried any of the xen drivers -- there are 3: xend, libxl and (old) xen-api. I would recommend figuring out how to start a simple VM using KVM+libvirt first to become familiar with the libvirt API and then switching over to xen.

A (very) simple first start would be to just generate the minimal .conf file (as mir-run does at the moment) and directly call 'xl/xm create -c'.

The more interesting second backend is automating Amazon EC2, for which bindings exist on Github (but I haven't tried). This requires signing the Xen kernel as an AKI image, and calling the right HTTP calls to upload it and register it, before spinning it up.  I can give you delegate access to my Amazon account, Vincent, if you don't have access to an EC2 account within Citrix.

Support for EC2 would be fantastic!

Cheers,

Dave