Blog: 2023-09-15

Setting up debian with qemu

First I made a larger qcow disk than the default cloud image:

qemu-img resize debian-12-larger-disk-amd64.qcow2 10G

Then I ran the installer

virt-install --memory 2048 --vcpus 2 --name qemu-debian-12 --disk debian-12-larger-disk-amd64.qcow2,device=disk,bus=virtio --graphics none --import --os-variant=debian12

When I was all done, I exited with CTRL-] - https://www.reddit.com/r/linuxadmin/comments/5gzdtk/properly_exiting_virtinstall/

Then I can boot the system with:

qemu-system-x86_64 -hda debian-12-larger-disk-amd64.qcow2 -nographic -m 2048

Finally...

Even got port forwarding working:

qemu-system-x86_64 -hda debian-12-larger-disk-amd64.qcow2 -nographic -m 2048 -nic user,model=virtio,hostfwd=tcp::8080-:80

Then from the host:

curl localhost:8080

Networking from guest to host appears to be working by default:

root@localhost:~# ip route
default via 10.0.2.2 dev ens3 proto dhcp src 10.0.2.15 metric 100
10.0.2.0/24 dev ens3 proto kernel scope link src 10.0.2.15 metric 100
10.0.2.2 dev ens3 proto dhcp scope link src 10.0.2.15 metric 100
10.0.2.3 dev ens3 proto dhcp scope link src 10.0.2.15 metric 100
root@localhost:~# curl -I 10.0.2.2:8000
HTTP/1.0 200 OK
Server: SimpleHTTP/0.6 Python/3.11.4
Date: Fri, 15 Sep 2023 07:53:21 GMT
Content-type: text/html; charset=utf-8
Content-Length: 4348

root@localhost:~#

References

https://wiki.debian.org/QEMU#Usage

https://techviewleo.com/run-debian-11-bullseye-on-kvm-using-qcow2-cloud-image/