Re: [Qemu-devel] [PATCH 01/11] QMP: Introduce specification file

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Avi Kivity wrote:

> On 06/25/2009 06:10 PM, Anthony Liguori wrote:
>>> I'd go further and make shell script support a non-goal.  Maybe the 
>>> majority of qemu control programs are scripts, but only a tiny 
>>> minority of VMs are controlled by shell scripts.  It is nearly 
>>> impossible to write a correct nontrivial program in bash; and scripts 
>>> will be slow due to the need to constantly fork/exec/connect.
>>>
>>> Serious management programs will be written in real languages, and 
>>> that's what we should optimize for.
>> I'm still inclined to stick with the text-based protocol.  libvirt 
>> likes it.  If Serious Management Programs want an RPC interface they 
>> can use libvirt.
> 
> That's really an onerous requirement.  What if libvirt lags behind 
> qemu?  What if libvirt doesn't want to support some feature?
> 
>> An RPC is overkill unless you also introduce things like life cycle 
>> management.  Otherwise, you could never realistically interact with 
>> QEMU without a intermediary that handled life cycle management (e.g. 
>> libvirt).
> 
> QMP is an RPC implemented over a text based protocol, with ad-hoc 
> marshalling.
> 
> I agree that you need something to reap dead qemus, but I don't think we 
> can force libvirt on people.
> 


Clearly I agree with Avi.
I am thinking for example that we could use the RPC protocol directly
from Xend and I am sure other people will find it useful too.