Messages in this thread | | | Date | Wed, 24 Aug 2011 12:19:12 +0300 | From | Pekka Enberg <> | Subject | Re: linux next: Native Linux KVM tool inclusion request |
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On 8/24/11 11:31 AM, Avi Kivity wrote: > On 08/23/2011 08:08 AM, Pekka Enberg wrote: >> As for changes, we've implemented rootfs over 9p with "kvm run" >> booting to host filesystem "/bin/sh" by default. > > Isn't this dangerous? Users expect virtualization to land them in > sandbox, but here an rm -rf / in the guest will happily junk the host > filesystem.
Not really because I never run the tool as root. However, you're right that we should not default to /bin/sh if you're root.
>> It still needs some >> work and we hope to enable networking too. We also have patches to use >> overlayfs so that the guest is able to use host filesystem in >> copy-on-write manner. > > Still dangerous (but just to the guest), since it's not a true > snapshot. If the host filesystem changes underneath the guest, it > will see partial and incoherent updates. Copy-on-write only works if > the host filesystem doesn't change.
That's a generic problem with overlayfs based solutions, isn't it? We're planning to use copy-on-write only on files that aren't supposed to change that often - like /usr and /lib. I suppose we should force shared files to be read-only in the guest.
Pekka
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