Experience with kvm - Gentoo host and RedHat guest

[depontius]

Can anyone here share experience with running Gentoo as a KVM host with a RedHat 5 guest?

My work requirements are pretty heavily tied to RHEL5, but I'd prefer to keep most of the machine native Gentoo. I've begun some basic searches against this stuff, found the Gentoo KVM guide, etc. However I presume that there are tips, techniques, etc that are only found by trial and error, and would like to start with someone else's experience as a reference. For a couple more gotchas...

We have pretty heavy MAC management here, so guests would likely have to NAT through the host, if I understand the networking options correctly.
The guests don't really need 3D graphics, though 2D performance will be important.
The hardware is a Thinkpad W510. (Core I7 quad)
The RHEL 5 install will likely be a bare (and barely usable, considering the ages of hardware and OS) install onto a partition as multiboot.

Thanks,
Dale
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.sigs waste space and bandwidth

[AngelKnight]

Not sure what "heavy MAC management" means. If it means that the Powers That Be refuse to allow an unrecognized MAC to pass ethernet frames, then indeed you may be stuck with NATting through the host. Otherwise, you could just set up a bridge and your RedHat VM and your Gentoo host will appear to the far end as if they're attached to a switch and then into the wall/floor/etc.

You're not obligated to partition off space right on the host's disk to make space for the RHEL5 guest. If you do, I recommend that you put it into an LVM (so a 1-partition LVM PV, with 1 VG inside, with the 1 LV inside which the RHEL5 guest will believe is an entire physical disk).

I haven't installed RHEL lately so I don't know if the boot image enables support for the "virtio block" device driver. You may be stuck with the performance penalty from KVM having to emulate an IDE or SCSI adapter until you can compile a kernel inside the RHEL guest with virtio support. Similar may go for network.

[depontius]

Heavy MAC management means all of the bad things you suggest, so I guess that means I'm stuck with NAT. I remember several years back someone complaining about this with respect to running Windows inside VMWare, and I don't believe they offered anything better. However the "new strategy" is to get rid of multiboot in favor of virtualization, so maybe they've relaxed the MAC requirements. But there's another strategic move to "endpoint registration", meaning only registered MACs can connect. So it's anyone's guess what the long-term prospects are going to be.

Which leads to another question... If I set up bridging, can I specify the MACs for the VMs, or are they somehow deterministic, so I can properly register them, if/when it becomes necessary? (I guess this can probably be gleaned from the Wiki, but it may also be something most people don't need to do, and therefore not documented.)

This also jogged my memory - the company is making VM images of several OS installs available internally. But those VM images are of course meant to run under RHEL6. Is KVM = KVM = KVM, so that I can set up Gentoo as a KVM host, and with a little care it'll run these VM images intended for RHEL6?
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.sigs waste space and bandwidth

[cach0rr0]