Re: [Qemu-devel] converging around a single guest agent

[Anthony Liguori]

On 11/15/2011 11:24 AM, Barak Azulay wrote:
> Hi,
>
> One of the breakout sessions during the ovirt workshop [1] was about the guest
> tools, and focused mainly on the ovirt-guest-agent [2].
>
> One of the issues discussed there, was the various existing guest agents out
> there, and the need to converge the efforts to a single agent that will serve
> all.
>
> while 4 agents were mentioned (Matahari, vdagent, qemu-ga&  ovirt-guest-agent)
> during that discussion, we narrowed it down to 2 candidates:
>
> qemu-ga (aka virt-agent):
> -------------------------
> - Qemu specific - it was aimed for specific qemu needs (mainly quiesce guest
> I/O)
> - Communicates directly with qemu  (not implemented yet)
> - Supports ?
> - So far linux only

But very easy to port.  It also should work on just about any Unix since its 
only dependency is glib.  Also:

 - exists in the QEMU repository

> - written in C
>
> Ovirt-guest-agent:
> ------------------
> - Has been around for a long time (~5 years) - considered stable
> - Started as rhevm specific but evolved a lot since then
> - Currently the only fully functional guest agent available for ovirt
> - Written in python
> - Some VDI related sub components are written in C&  C++
> - Supports a well defined list of message types / protocol [3]
> - Supports the folowing guest OSs
>    Linux: RHEL5, RHEL6 F15, F16(soon)
>    Windows: xp, 2k3 (32/64), w7 (32/64), 2k8 (32/64/R2)

The guest agent we use in QEMU exists to implement QEMU specific functionality. 
 I think one challenge that comes up here is that the ovirt guest agent has a 
very different scope than the QEMU agent.  The ovirt guest agent has a very 
ovirt-engine centric scope.

> The need to converge is obvious, and now that ovirt-guest-agent is opensourced
> under the ovirt stack, and since it already produces value for enterprise
> installations, and is cross platform, I offer to join hands around ovirt-
> guest-agent and formalize a single code base that will serve us all.

You are basically saying, stop what you guys are doing and work on our code 
because it's better.  That's not really convergence.

If you want to talk about convergence, the discussion should start around 
collecting requirements.  We can then figure out if the two sets of requirements 
are strictly overlapping or if there are any requirements that are fundamentally 
in opposition.

Regards,

Anthony Liguori