converging around a single guest agent

[Perry Myers]

On 11/15/2011 02:13 PM, Carl Trieloff wrote:
> 
> Matahari is a can be bound to any agent, i.e. it adds transport,
> security etc etc so is not an exclusive or discussion. It can be seen as
> an encapsulation.

Yes, but when we discussed matahari in the context of a ubiquitous
lightweight virt agent (for both libvirt/qemu/oVirt) it was rejected due
to complexity and dependencies.

Our thinking was that matahari should not be required for core
functionality for qemu/libvirt/oVirt, but can instead be used in
conjunction with the lightweight guest agent/transport to provide higher
level mgmt functionality

Here's a quick flow of the Matahari path from guest to host, and why
it's too complex to be suitable for these use cases:

QMF Guest Agent(s) <QMF> Guest qpid Broker <QMF> Guest VIOS Proxy <QMF
over virtio-serial> Host VIOS Proxy <QMF> Host qpid Broker <QMF> QMF
Host Console

Compare that to:

ovirt-guest-agent <JSON over virtio-serial> vdsm

qemu-guest agent <JSON over virtio-serial> qemu <QMP API> libvirtd

Perry

> Carl.
> 
> 
> On 11/15/2011 12:24 PM, 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
>> - 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 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.
>>
>> git @ git://gerrit.ovirt.org/ovirt-guest-agent
>>
>> Thoughts ?
>>
>> Thanks
>> Barak Azulay
>>
>> [1] http://www.ovirt.org/news-and-events/workshop
>> [2] http://www.ovirt.org/wiki/File:Ovirt-guest-agent.odp
>> [3] http://www.ovirt.org/wiki/Ovirt_guest_agent
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