Kushal Das

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How to mount a raw guest image?

While testing the latest Fedora 24 cloud images, I had to mount it locally so that I inspect the files inside. We can do this by using the offset value calculated from the fdisk command.

# fdisk -l /var/lib/imagefactory/storage/7c34e40b-b27c-4cd9-ae05-459c93c98005.body
Disk /var/lib/imagefactory/storage/7c34e40b-b27c-4cd9-ae05-459c93c98005.body: 3 GiB, 3221225472 bytes, 6291456 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xfeecffb4

Device                                                                   Boot Start     End Sectors Size Id Type
/var/lib/imagefactory/storage/7c34e40b-b27c-4cd9-ae05-459c93c98005.body1 *     2048 6291455 6289408   3G 83 Linux

In this case the start value is 2048, and each sector is 512 bytes, so our offset value is 2048 * 512 = 1048576.

# mount -o offset=1048576 /var/lib/imagefactory/storage/7c34e40b-b27c-4cd9-ae05-459c93c98005.body /mnt
[root@fedora-build f23]# ls /mnt/
bin  boot  dev  etc  home  lib  lib64  lost+found  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var