[libvirt-users] Broken OS when booting rootfs from 9p share

Tue Feb 24 22:56:50 UTC 2015


On Tue, 2015-02-24 at 16:05 -0500, Laine Stump wrote:
> On 02/24/2015 03:37 PM, Olivier Mauras wrote:
> >> Hello,
> >>
> >> I've been trying to boot a VM with the rootfs being a 9P share from
> >> the host. The VM OS is centos 7.
> >> The OS boots but no services can work and it appears that the
> >> authentication system is broken.
> >>
> >> Now the funny thing is that booting the same OS on the same 9P share
> >> manually with Qemu works as expected with a fully functionnal OS... So
> >> I'm wondering what could libvirt do that render the OS on the share
> >> broken - Something with rights ?
> >> Selinux is disabled on the host, and accessmode to the share is set to
> >> passthrough in both cases.
> >>
> >> Here's my working Qemu line:
> >> qemu
> >> -kernel /srv/overlay/kernels/grsec-3.14.33-101/vmlinuz-3.14.33-101.el6.x86_64 \
> >>
> >> -initrd /srv/overlay/kernels/grsec-3.14.33-101/initramfs-3.14.33-101.el6.x86_64.img \
> >>   -fsdev
> >> local,id=r,path=/srv/overlay/run/irc,security_model=passthrough \
> >>   -device virtio-9p-pci,fsdev=r,mount_tag=root \
> >>   -nographic \
> >>   -m 256M \
> >>   -machine pc-i440fx-2.1,accel=kvm \
> >>   -netdev tap,id=net0 -device
> >> virtio-net,netdev=net0,mac=52:54:00:12:36:34 \
> >>   -smp 1,sockets=1,cores=1 \
> >>   -append 'root=virtfs:root rootflags=trans=virtio,version=9p2000.u ro
> >> rootfstype=9p console=ttyS0'
> >>
> >> And here my libvirt VM config:
> >> <domain type='kvm'>
> >>   <name>irc</name>
> >>   <uuid>ffbd32eb-a693-eadd-8923-18de80137472</uuid>
> >>   <memory unit='KiB'>262144</memory>
> >>   <currentMemory unit='KiB'>262144</currentMemory>
> >>   <vcpu placement='static'>1</vcpu>
> >>   <os>
> >>     <type arch='x86_64' machine='pc-i440fx-2.1'>hvm</type>
> >>
> >> <kernel>/srv/overlay/kernels/grsec-3.14.33-101/vmlinuz-3.14.33-101.el6.x86_64</kernel>
> >>
> >> <initrd>/srv/overlay/kernels/grsec-3.14.33-101/initramfs-3.14.33-101.el6.x86_64.img</initrd>
> >>     <cmdline>root=virtfs:root rootflags=trans=virtio,version=9p2000.u
> >> ro rootfstype=9p</cmdline>
> >>     <boot dev='hd'/>
> >>   </os>
> >>   <features>
> >>     <acpi/>
> >>     <apic/>
> >>     <pae/>
> >>   </features>
> >>   <clock offset='utc'/>
> >>   <on_poweroff>destroy</on_poweroff>
> >>   <on_reboot>restart</on_reboot>
> >>   <on_crash>restart</on_crash>
> >>   <devices>
> >>     <emulator>/usr/bin/qemu-system-x86_64</emulator>
> >>     <controller type='usb' index='0'>
> >>       <address type='pci' domain='0x0000' bus='0x00' slot='0x01'
> >> function='0x2'/>
> >>     </controller>
> >>     <controller type='pci' index='0' model='pci-root'/>
> >>     <filesystem type='mount' accessmode='passthrough'>
> >>       <source dir='/srv/overlay/run/irc'/>
> >>       <target dir='root'/>
> >>       <address type='pci' domain='0x0000' bus='0x00' slot='0x05'
> >> function='0x0'/>
> >>     </filesystem>
> >>     <interface type='bridge'>
> >>       <mac address='52:54:00:00:36:34'/>
> >>       <source bridge='br0'/>
> >>       <model type='virtio'/>
> >>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03'
> >> function='0x0'/>
> >>     </interface>
> >>     <serial type='pty'>
> >>       <target port='0'/>
> >>     </serial>
> >>     <console type='pty'>
> >>       <target type='serial' port='0'/>
> >>     </console>
> >>     <input type='mouse' bus='ps2'/>
> >>     <input type='keyboard' bus='ps2'/>
> >>     <graphics type='vnc' port='-1' autoport='yes'/>
> >>     <video>
> >>       <model type='cirrus' vram='9216' heads='1'/>
> >>       <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
> >> function='0x0'/>
> >>     </video>
> >>     <memballoon model='virtio'>
> >>       <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
> >> function='0x0'/>
> >>     </memballoon>
> >>   </devices>
> >> </domain>
> >>
> >>
> >> My libvirt version is 1.2.9, and qemu is 2.1.2.
> >>
> >> Thanks for your help,
> >>
> >> Olivier
> >>
> >>  
> >> _______________________________________________
> >> libvirt-users mailing list
> >> libvirt-users at redhat.com
> >> https://www.redhat.com/mailman/listinfo/libvirt-users
> > So I updated libvirt to 1.2.12 and qemu to 2.1.3 and it still gives me
> > the exact same behaviour ... 
> > Could it be that the share was created with an old version of
> > virt-manager redenring in old/broken XML?  From Qemu config example i
> > don't see how my XML could be incorrect.
> >
> > Any idea ?
> 
> I know nothing about the 9p filesystem, but since you have a qemu
> commandline that works and a libvirt config that doesn't, the next
> logical step would be to provide the non-working qemu commandline
> generated by libvirt. You can find this at the end of the log file
> /var/log/libvirt/qemu/irc.log.
Here it is... A bit more complex :)

LC_ALL=C PATH=/sbin:/usr/sbin:/bin:/usr/bin
QEMU_AUDIO_DRV=none /usr/bin/qemu-system-x86_64 -name irc -S -machine
pc-i440fx-2.1,accel=kvm,usb=off -m 256 -realtime mlock=off -smp
1,sockets=1,cores=1,threads=1 -uuid ffbd32eb-a693-eadd-8923-18de80137472
-no-user-config -nodefaults -chardev
socket,id=charmonitor,path=/var/lib/libvirt/qemu/irc.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -no-acpi -boot strict=on -kernel /srv/overlay/kernels/grsec-3.14.33-101/vmlinuz-3.14.33-101.el6.x86_64 -initrd /srv/overlay/kernels/grsec-3.14.33-101/initramfs-3.14.33-101.el6.x86_64.img -append root=virtfs:root rootflags=trans=virtio,version=9p2000.u rw rootfstype=9p -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -fsdev local,security_model=passthrough,id=fsdev-fs0,path=/srv/overlay/run/irc -device virtio-9p-pci,id=fs0,fsdev=fsdev-fs0,mount_tag=root,bus=pci.0,addr=0x5 -netdev tap,fd=27,id=hostnet0,vhost=on,vhostfd=28 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:00:10:10,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc 127.0.0.1:3 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4 -msg timestamp=on

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