Installing Debian via qemu
I’ve been experimenting with kvm and qemu and run into some conceptual and practical problems. Here are some of my discoveries and short cuts.
I started by downloading the netinst Debian install image as debian-503-amd64-netinst.iso. Next I created an empty image:
qemu-img create -f raw default.img 3GB
This file will hold the virtual server.
Next, I launched the virtual server, booting from the debian installer, passing the file I just created as the first hard drive:
qemu-system-x86_64 -boot d -cdrom debian-503-amd64-netinst.iso -hda default.img -curses
This command is like booting a server with a single hard drive and the Debian install CD in the CD ROM drive (and configuring your bios to boot from the CD).
I pass the -curses option to tell qemu to not try to use the graphics card (since I’m doing this over ssh).
And here’s the real trick: Since the Debian installer tries to use frame buffers, I just got “640 x 480 Graphic Mode” on my screen. Following the Debian manual, I hit “Esc” on my keyboard and was magically dropped into text mode. Next I typed:
to launch the installer and ensure that frame buffer mode was disabled. From that point on I was taken through a text-based installation.
Everything went smoothly until the Grub install where I seemed to be hit with a qemu/grub 1 bug.
I killed the qemu process and made a bootable grub iso:
mkdir -p grub/boot/grub cp /usr/lib/grub/x86_64-pc/stage2_eltorito grub/boot/grub/ mkisofs -R -b grub/boot/grub/stage2_eltorito -no-emul-boot -boot-load-size 4 -boot-info-table -o grub.iso grub
Those steps created a file called grub.iso. I then booted with that file:
qemu-system-x86_64 -boot d -cdrom grub.iso -hda default.img -curses
And was dropped into a grub shell. I typed:
root (hd0,0) kernel /boot/vmlinuz-2.6.26-2-amd64 root=/dev/hda1 ro initrd /boot/initrd.img-2.6.26-2-amd64
And finally typed: boot and behold the installation booted!
Now the problem is… how do get grub properly installed??
Well… the solutions seems to be to install grub2. Before I could do that, I had to figure out how to get networking properly setup. Thanks to some help I changed the /etc/network/interfaces file on the host to:
auto br0 iface br0 inet static address 126.96.36.199 netmask 255.255.255.224 gateway 188.8.131.52 bridge_ports eth0
And edited /etc/qemu-up to:
sudo -p "Password for $0:" /sbin/ifconfig $1 0.0.0.0 promisc up sudo /usr/sbin/brctl addif br0 $1
Then, I restarted the virtual server with:
qemu-system-x86_64 -boot d -cdrom grub.iso -hda default.img -curses -net nic -net tap
I went through the same grub business. Then, from inside the virtual host, I configured /etc/network/interfaces with a real IP address.
With network access, I installed grub2 and then ran:
grub-intall /dev/hda udpate-grub shutdown -h now
And then restarted the virtual server with: qemu-system-x86_64 -hda default.img -curses -net nic -net tap
grub2 is graphical - so I can’t access it during the bootup (there’s probably a text mode command for grub2 somehwere).
At this point I finally got around to reading the README.Debian file in the qemu docs directory and learned about the Debian command qemu-make-debian-root. Wow. That’s makes things a lot easier.
According to the docs you can run:
qemu-make-debian-root 3000 lenny http://ftp.debian.org/ debian.img
To use deboostrap to create a debian image. Then, launch with:
qemu debian.img -kernel /vmlinuz
Haven’t gotten this to work though…
And another thing - I realized that I didn’t have kqemu installed (check for /dev/kqemu). I installed it with:
aptitude install kqemu-sources
And then ran:
To build the module.
modprobe -v kqemu
To load the module.