How to mount a qcow2 disk image

mount_qcow2.md

How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

Step 2 - Connect the QCOW2 as network block device

qemu-nbd --connect=/dev/nbd0 /var/lib/vz/images/100/vm-100-disk-1.qcow2

Step 3 - Find The Virtual Machine Partitions

fdisk /dev/nbd0 -l

Step 4 - Mount the partition from the VM

mount /dev/nbd0p1 /mnt/somepoint/

Step 5 - After you done, unmount and disconnect

umount /mnt/somepoint/
qemu-nbd --disconnect /dev/nbd0
rmmod nbd

@0xcpu:

See this link

As far as I know the "BIOS Boot Partition" does not contain any filesystem but only the Grub image. It is the space you need that would otherwise be put somewhere between the MBR and the first partition.

Seems like you wouldn't wan to "mount" that but rather just mount the other two partitions.

I successfully mounted but I can't able copy and paste files

thanks! found that via google!

I had the same problem as @poma. fdisk listed the partitions but there were no corresponding device files. partx did not help. Run as partx -v -a /dev/nbd0 it complained about "invalid argument" and did not create anything.

kpartx helped. First I checked with kpartx -l /dev/nbd0, then actually created the device files with kpartx -a /dev/nbd0. The device files appeared in /dev/mapper.

thanks! very useful!

gives me this error, since i made my qcow2 an LVM

“mount: unknown filesystem type LVM2_member”

Is there any other way for me to mount this as an LVM?

Is there any other way for me to mount this as an LVM?

Hello from December 2021 :)

1. Run sudo pvs to get a volume group (column VG) for your device.
2. Run sudo lvdisplay ⟨your VG⟩ to get a LV Path.
3. Run sudo vgchange -a y to activate all groups.
4. Now you can mount it: sudo mount ⟨your LV Path⟩ /mnt/somepoint

How to change the "config.plist" file, I don't have permission to edit it.

Thanks

Is there any way to see path of the qcow2 file connected to nbd device (after successful "qemu-nbd -c")?
for example, want to see file name being mounted on /dev/nbd0 from a monitoring program.

works fine under OS

lsb_release -a
LSB Version:	core-11.1.0ubuntu4-noarch:printing-11.1.0ubuntu4-noarch:security-11.1.0ubuntu4-noarch
Distributor ID:	Ubuntu
Description:	Ubuntu 22.04.1 LTS
Release:	22.04
Codename:	jammy

i had .img file ending instead of .qcow2

after i checked with qemu-img info XXXX.img

i see that it is a qcow2 format

thanks a lot

gives me this error, since i made my qcow2 an LVM

“mount: unknown filesystem type LVM2_member”

Is there any other way for me to mount this as an LVM?

you have to remove missing disk from LVM member group, you can read my howto to fix it here:
(http://aysad.cloudns.cc/blog/2023/11/28/lvm/raid1/disk/mount/recovery/howto/)

Thanks. Ckear, concise. Worked on Fedora Server 38.

Very useful, but I think it worth to add nbds_max=1 (or 2) to the modprobe, so it only creates one or two devices, instead of 16.