Re: [libvirt] [PATCH] docs: formatdomain: Specify the default value of 'check' attribute

On Tue, Jan 09, 2018 at 04:37:10PM +0100, Jiri Denemark wrote: [...] [...] Yep, I missed to distinguish that detail. That's all good. If you think nothing needs to be clarified here, that's OK. (Some admins who operate a lot of VMs with libvirt will disagree with you, though.) And as we saw on IRC, `virt-install` muddies the water in this case by gratuitously adding a CPU parameter with check='full' (even if a user didn't explicitly specify it) when you simply import an image and look at the run-time guest XML: $> virt-install --name vm1 --ram 2048 \ --disk path=./vm1.qcow2,format=qcow2 --nographics \ --import --os-variant fedora27 $> virsh dumpxml vm1 | grep check <cpu mode='custom' match='exact' check='full'> (You might, fairly, argue here that: "Well, that's a bug in `virt-install`, go complain there.") It all comes across as messy to an unsuspecting admin. (If a competent admin finds it confusing, good luck to new admins who want to wrap their head around this.) - - - Background for others reading: The admin who reported this was confused when he was creating guests with `virt-install`, which adds check='full' (as noted earlier), and the guest throws: error: Failed to start domain foo.org error: operation failed: guest CPU doesn't match specification: extra features: vme,arat So "somehow" QEMU added the CPU features 'vme' and 'arat' by itself, now you have to specify them in libvirt. So the admin ended up with a `sed` one-liner that updates the guest XML with the missing features: sed -i -e "s-</cpu>-<feature policy='require' name='vme'/></cpu>-" sed -i -e "s-</cpu>-<feature policy='require' name='arat'/></cpu>-" Versions: libvirt 3.2 and QEMU 2.9