On Wed, Jan 26, 2011 at 4:05 PM, Iustin Pop <ius...@google.com> wrote:
> On Mon, Jan 17, 2011 at 03:58:51PM -0200, Miguel Di Ciurcio Filho wrote:
>> Hi list,
>>
>> I'm hacking some code to use QMP[1] to control KVM instances, instead
>> of the traditional monitor.
>
> Interesting.
>
>> Commands to the monitor are concatenated with arguments when they are
>> required and passed 'ready to run' to _CallMonitorCommand().
>>
>> `egrep _CallMonitorCommand lib/hypervisor/hv_kvm.py` to have look.
>>
>> Some issues I've identified:
>>
>> 1) QMP arguments and monitor arguments sometimes differ:
>> `migrate -d tcp:1.1.1.1:5555`
>> VS
>> { "execute": "migrate", "arguments": { "uri": "tcp:1.1.1.1:5555" } }
>>
>> 2) QMP and traditional monitor commands some times differ, eg:
>> `change vnc password`
>> VS
>> { "execute": "set_password", "arguments": { "protocol": "vnc",
>> "password": "secret" } }
>>
>> It is mandatory to support both QMP and the traditional monitor, so
>> here are the questions I have:
>>
>> 1) Would it be better to abstract each command to a method
>> _ChangeVNCPassword(), and inside this methods verify the arguments and
>> make the call to QMP or the traditional monitor.
>
> This would be lot of work…
>
>> 2) Use a generic and unique interface, and then check command, the
>> arguments and then call _CallMonitorCommand() or _CallQMPCommand()
>
> … but this doesn't work due to changed arguments.
>
> Have you tried to talk with the QMP developers about standardizing the
> argument/commands between QMP and the standard monitor?
>
I think the traditional commands/arguments are fixed because they are
a historical interface, and it's a bit late to change the QMP protocol
now... I think we need to implement it, and do it in a way so that we
can use it when it's available, and in the future just drop
traditional monitor support when we decide to depend on a KVM version
with QMP enabled (not for another few versions of Ganeti). :)
Is it possible to have a table with QMP and traditional arguments
together, and then lookup at runtime what string to use depending on
whether QMP is enabled or not? :)
Thanks,
Guido
