Hello,

I'm playing with an openstack lab environment based on Icehouse on CentOS 7 and nested virtualization.

Some details about the infra.

L0 Host is on Fedora 23: my laptop with ssd disk and 16Gb of ram, using Qemu/KVM and virt-manager

L1 Host is CentOS 7 with 4Gb of ram and configured with IceHouse rdo repo (EOL7) (copy host cpu config in virt-manager of Fedora 23) and packstack allinone

L2 is Centos 7 cloud image configured with 1Gb of ram

CentOS-7-x86_64-GenericCloud.qcow2 download by end of February 2016

I'm able to do all on this L2 guest (eg ssh login with centos user through key and attch floating ip) but I noticed 2 things:

1) I was not able to boot because the VM always remained stuck at boot at message:

...trying to set up timer as Virtual Wire IRQ...

I found this

https://bugzilla.redhat.com/show_bug.cgi?id=1175502

but actually my VM is nested with kvm

command line run by L1 is:

qemu 31641 1 88 13:36 ? 00:05:47 /usr/libexec/qemu-kvm -name instance-00000006 -S -machine pc-i440fx-rhel7.0.0,accel=tcg,usb=off -m 1024 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid e0680ada-1fc8-4d7a-829b-ba581a6252ef -smbios type=1,manufacturer=RDO Project,product=OpenStack Nova,version=2014.1.5-1.el7.centos,serial=14603773-bb9a-46e3-b333-07e0b68e65ac,uuid=e0680ada-1fc8-4d7a-829b-ba581a6252ef -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-instance-00000006/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/nova/instances/e0680ada-1fc8-4d7a-829b-ba581a6252ef/disk,if=none,id=drive-virtio-disk0,format=qcow2,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/var/lib/nova/instances/e0680ada-1fc8-4d7a-829b-ba581a6252ef/disk.local,if=none,id=drive-virtio-disk1,format=qcow2,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk1,id=virtio-disk1 -drive file=/var/lib/nova/instances/e0680ada-1fc8-4d7a-829b-ba581a6252ef/disk.swap,if=none,id=drive-virtio-disk2,format=qcow2,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk2,id=virtio-disk2 -netdev tap,fd=27,id=hostnet0 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=fa:16:3e:c5:ff:fc,bus=pci.0,addr=0x3 -chardev file,id=charserial0,path=/var/lib/nova/instances/e0680ada-1fc8-4d7a-829b-ba581a6252ef/console.log -device isa-serial,chardev=charserial0,id=serial0 -chardev pty,id=charserial1 -device isa-serial,chardev=charserial1,id=serial1 -device usb-tablet,id=input0 -vnc 0.0.0.0:1 -k en-us -vga cirrus -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -msg timestamp=on

I solved the boot problem using extra property for the C7 image:

glance image-update --property kernel_extra_args="no_timer_check"

and now I'm able to boot without problems

Is it ok my approach? In case is it possible to configure the image itself directly? Or is there any drawback in setting that parameter?

2) Just at first boot the VM uses much cpu because of this process:

root 3119 2024 4 12:42 ? 00:00:09 /bin/bash /usr/sbin/dracut --hostonly --hostonly-cmdline --hostonly-i18n -o plymouth dash resume ifcfg -f /boot/initramfs-3.10.0-327.10.1.el7.x86_64kdump.img 3.10.0-327.10.1.el7.x86_64

What is it? Can I avoid in any way? For about 5-10 minutes my L0 laptop runs at 80 degrees... ;-)

Is the load normal during that phase due to my resource constraints or is it in any way caused by the extra setting in 1) ?

Thanks in advance!

Gianluca