This container was built to create a QCOW2 image and connect it to a /dev/nbd* device using qemu-nbd. It is mostly just a useful hack for getting storage solution working in KinD on non-linux machines like in this tutorial.
Create a docker volume to persist your qemu images.
docker volume create qemu-images
Start the container so that it will restart unless manually stopped.
docker run -d --restart unless-stopped --pid=host --privileged \
-v "qemu-images:/data/qemu-images" -v '/dev:/dev' \
-e QCOW2_IMG_PATH=/data/qemu-images/developer.qcow2 \
-e NBD_DEV_PATH=/dev/nbd0 \
-e QCOW2_IMG_SIZE=60G \
-e VG_NAME=myvolgrp \
--name auto-nbd \
ghcr.io/protosam/auto-nbd
Accessing the container can be useful if you want to view storage details.
# docker exec -it auto-nbd bash
root@9d7c9984a5e9:/# vgs
VG #PV #LV #SN Attr VSize VFree
myvolgrp 1 0 0 wz--n- <60.00g <60.00g
root@9d7c9984a5e9:/# lsns -t pid
NS TYPE NPROCS PID USER COMMAND
4026531836 pid 148 1 root /sbin/init
4026532226 pid 1 979 root /allowlist
4026532395 pid 1 1025 root /artifactory-agent --docker-desktop-mode
4026532397 pid 1 1229 root dhcpcd: [master] [ip4]
4026532400 pid 1 1187 root /devenv-server -socket /run/guest-services/devenv-volumes.sock
4026532403 pid 1 1331 root /usr/bin/dns-forwarder -dns.port 53 -conf /etc/coredns/Corefile
4026532406 pid 1 1447 root /http-proxy
4026532408 pid 1 1506 root /usr/bin/kmsg
4026532526 pid 2 1640 root /start 30
4026532530 pid 1 1801 root /usr/bin/trim-after-delete -- /sbin/fstrim /var/lib/docker
4026532532 pid 1 1852 root /usr/bin/volume-contents
4026532534 pid 1 1898 root /usr/bin/vpnkit-forwarder -data-connect /run/host-services/vpnkit-data.sock -data-listen /run/guest-services/wsl2-expose-ports.sock
4026532666 pid 1 25935 root bash
Volumes can be managed inside the container. Here is how to get in and remove a volume.
% docker exec -it auto-nbd bash
root@b843c9fe6d5d:/# vgs
VG #PV #LV #SN Attr VSize VFree
myvolgrp 1 10 0 wz--n- <60.00g <50.00g
root@b843c9fe6d5d:/# lvs --noheading
pvc-4ba801bf-b7f6-4d85-ba69-4a51b52ac76a myvolgrp -wi------- 1.00g
pvc-5447de1a-b983-4de1-8dfd-ec6f77e52419 myvolgrp -wi------- 1.00g
pvc-68f79916-1f64-46f2-babe-2aaf74f0ad2b myvolgrp -wi------- 1.00g
pvc-6ff7eb10-af74-49b5-9927-f06cce4279a1 myvolgrp -wi------- 1.00g
pvc-a8a5c7f4-5c0a-4c73-bd21-16b3dc50b27b myvolgrp -wi------- 1.00g
pvc-a9af3318-2170-4099-ae46-94fc415199c4 myvolgrp -wi------- 1.00g
pvc-fd34d484-6624-457f-b6aa-e5c65db2c27d myvolgrp -wi------- 1.00g
root@b843c9fe6d5d:/# lvremove /dev/myvolgrp/pvc-4ba801bf-b7f6-4d85-ba69-4a51b52ac76a
Logical volume "pvc-4ba801bf-b7f6-4d85-ba69-4a51b52ac76a" successfully removed