Re: [RFC] Unify KVM kernel-space and user-space code into a singleproject

From: Antoine Martin
Date: Tue Mar 23 2010 - 06:28:39 EST


On 03/23/2010 05:13 PM, Kevin Wolf wrote:
Am 22.03.2010 23:06, schrieb Anthony Liguori:
On 03/22/2010 02:47 PM, Avi Kivity wrote:
Having qemu enumerate guests one way or another is not a good idea IMO
since it is focused on one guest and doesn't have a system-wide entity.
There always needs to be a system wide entity. There are two ways to
enumerate instances from that system wide entity. You can centralize
the creation of instances and there by maintain an list of current
instances. You can also allow instances to be created in a
decentralized manner and provide a standard mechanism for instances to
register themselves with the system wide entity.

IOW, it's the difference between asking libvirtd to exec(qemu) vs
allowing a user to exec(qemu) and having qemu connect to a well known
unix domain socket for libvirt to tell libvirtd that it exists.
I think the latter is exactly what I would want for myself. I do see the
advantages of having a central instance, but I really don't want to
bother with libvirt configuration files or even GUIs just to get an
ad-hoc VM up when I can simply run "qemu -hda hd.img -m 1024". Let alone
that I usually want to have full control over qemu, including monitor
access and small details available as command line options.

I know that I'm not the average user with these requirements, but still
I am one user and do have these requirements. If I could just install
libvirt, continue using qemu as I always did and libvirt picked my VMs
up for things like global enumeration, that would be more or less the
optimal thing for me.
+1
And it would also make it more likely that users like us would convert to libvirt in the long run, by providing an easy and integrated transition path.
I've had another look at libvirt, and one of the things that is holding me back is the cost of moving existing scripts to libvirt. If it could just pick up what I have (at least in part), then I don't have to.

Antoine

Kevin
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/