Hello, I'm struggling to make a cloned CentOS 7 VM (under KVM) to work. The VM was cloned using mondorestore. Restore appears successful but the VM won't boot; see: http://iweb.noa.gr/files/centos7/supergrub2-scratchvm-20170503-04.png I booted with CentOS 7 disk in troubleshooting mode (where the virtual disk was automatically mounted without issues) and I tried to repair: http://iweb.noa.gr/files/centos7/el7-rescue-scratchvm-20170502-01.png Also: # grub2-mkconfig -o /boot/grub2/grub.cfg ... /usr/sbin/grub2-probe: error: unknown filesystem. I then tried to repair using: https://sourceforge.net/p/boot-repair-cd/home/Home/ but it didn't manage to solve the problem. (It reported success but the VM still won't boot.) More interesting was the effort with the supergrub2 disk: http://www.supergrubdisk.org/super-grub2-disk/ This managed to identify the available "boot methods" and allowed me to boot correctly. See screenshots: http://iweb.noa.gr/files/centos7/supergrub2-scratchvm-20170503-00.png http://iweb.noa.gr/files/centos7/supergrub2-scratchvm-20170503-01.png http://iweb.noa.gr/files/centos7/supergrub2-scratchvm-20170503-02.png Once I logged in, I checked /etc/fstab and /boot/grub2/grub.cfg but I didn't see any obvious problem. The are here as well: http://iweb.noa.gr/files/centos7/fstab http://iweb.noa.gr/files/centos7/grub.cfg However, I also followed these directions: https://www.techbrown.com/reinstall-grub2-boot-loader-centos-7-rhel-7.shtml to rebuild grub2.conf. The commands were completed successfully. Unfortunately, the OS still won't boot: same issue, see: http://iweb.noa.gr/files/centos7/supergrub2-scratchvm-20170503-04.png I again tried to boot using the supergrub2 disk; this time the boot method detection produced the (slightly different) list you see in image: http://iweb.noa.gr/files/centos7/supergrub2-scratchvm-20170503-05.png Using the supergrub2 disk I can boot and login successfully. Otherwise (i.e. directly) the box won't boot. As I know little about grub2 (and low-level linux) to troubleshoot the issue, can you please help identify and correct the problem? Why the VM always refuses to boot? Which is the reported device (on image -04) that remains unrecognized? I looked into /boot/grub/grub2.cfg but I didn't see any such UUID there. Where may it be referenced to be used during the boot process? Note: I never have such issues when restoring (using mondorestore) CentOS 5 or CentOS 6 mondoarchive backups (even on dissimilar virtual hardware). Can you please help me identify the problem, based on the above info, and make the VM normally bootable? Many thanks, Nick
