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

[Chris Webb]

Anthony Liguori <address@hidden> writes:

> There are two questions to resolve.  The first is whether we should  
> continue with the current direction (line-based protocol) or whether we  
> should switch to an RPC.  The second question is which RPC we should use.
>
> I'm not at all convinced that we should switch to an RPC mechanism in  
> the first place.  Perhaps someone could summarize the advantages of  
> doing this because right now, I don't see many.
>
> With respect to RPC choice, if we did go that route, I'd be very  
> concerned about using jsonrpc verses a more well established rpc.  I  
> would honestly prefer xml-rpc over jsonrpc.

We are an example of a end user of qemu (or more specifically qemu-kvm) that
doesn't go via a management layer like libvirt. Our management shell scripts
directly control the virtual machines using the current line-oriented 'human
friendly' monitor. This is a bit of a pain, but not too bad in practice.

A more regular and well defined line-based protocol would be a big plus for
us, whereas something like jsonrpc or xml-rpc would be a complete disaster
to call from the shell---less useful than the current human oriented monitor
rather than more so.

(Aside from the practical question, personally I share your gut feeling that
it seems like a sledgehammer to crack a nut and not a good fit at all for
this layer of the stack.)

Cheers,

Chris.