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Re: [Qemu-devel] Adding an IPMI BMC device to KVM
From: |
Avi Kivity |
Subject: |
Re: [Qemu-devel] Adding an IPMI BMC device to KVM |
Date: |
Mon, 07 May 2012 17:44:23 +0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 |
On 05/07/2012 05:30 PM, Anthony Liguori wrote:
> On 05/06/2012 09:39 AM, Avi Kivity wrote:
>> On 05/06/2012 05:35 PM, Anthony Liguori wrote:
>>> On 05/06/2012 08:11 AM, Avi Kivity wrote:
>>> libvirt is essentially the BMC for a virtual guest. I would suggest
>>> looking at implementing an IPMI interface to libvirt and exposing it
>>> to the guest through a USB RNDIS device.
>>>
>>
>> That's the first option. One unanswered question is what to do when the
>> guest is down? Someone should listen for IPMI events, but we can't make
>> it libvirt unconditionally, since many instances of libvirt are active
>> at any one time.
>>
>> Note the IPMI external interface needs to be migrated, like any other.
>
> For all intents and purposes, the BMC/RSA is a separate physical
> machine.
That's true for any other card on a machine.
> If you really wanted to model it, you would launch two instances of
> QEMU. The BMC instance would have a virtual NIC and would share a USB
> bus with the slave QEMU instance (probably via USBoIP). The USB bus
> is how the BMC exposes IPMI to the guest (via a USB rndis adapter),
> remote media, etc. I believe some BMC's also expose IPMI over i2c but
> that's pretty low bandwidth.
That is one way to do it. Figure out the interactions between two
different parts in a machine, define an interface for them to
communicate, and split them into two processes. We don't usually do
that; I believe your motivation is that the two have different power
domains (but then so do NICs with wake-on-LAN support).
> At any rate, you would have some sort of virtual hardware device that
> essentially spoke QMP to the slave instance. You could just do
> virtio-serial and call it a day actually.
Sorry I lost you. Which is the master and which is the slave?
> It really boils down to what you are trying to do. If you want to
> just get some piece of software working that expects to do IPMI, the
> easiest thing to do is run IPMI in the host and use a USB rndis
> interface to interact with it.
That would be most strange. A remote client connecting to the IPMI
interface would control the power level of the host, not the guest.
> I don't think there's a tremendous amount of value in QEMU making
> itself look like an IBM IMM or whatever HP/Dell's equivalent is. As I
> said, these stacks are hugely complicated and there are better ways of
> doing out of band management (like talk to libvirt directly).
I have to agree here.
--
error compiling committee.c: too many arguments to function
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Avi Kivity, 2012/05/06
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Anthony Liguori, 2012/05/06
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Avi Kivity, 2012/05/06
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Anthony Liguori, 2012/05/07
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM,
Avi Kivity <=
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Anthony Liguori, 2012/05/07
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Avi Kivity, 2012/05/07
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Anthony Liguori, 2012/05/07
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Corey Minyard, 2012/05/07
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Anthony Liguori, 2012/05/07
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Dave Allan, 2012/05/08
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Corey Minyard, 2012/05/07
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Stefan Hajnoczi, 2012/05/18
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Corey Minyard, 2012/05/18
- Re: [Qemu-devel] Adding an IPMI BMC device to KVM, Corey Minyard, 2012/05/18