Virtualization

Recover a Broken KVM Virtual Machine

Reproduce a safe domain start failure; Identify the first causal error across virsh, journal, and QEMU logs; Repair only the bad definition or path; Start the original guest and verify both disks and networks.

By InventiveHQ Team

Episode 11 of the InventiveHQ KVM virtualization series.

Lab verified July 2026 · Ubuntu 26.04 · libvirt 12.0.0 · QEMU 10.2.1

What this episode proves

  • Reproduce a safe domain start failure
  • Identify the first causal error across virsh, journal, and QEMU logs
  • Repair only the bad definition or path
  • Start the original guest and verify both disks and networks

Validated workflow

1. Reproduce a safe domain start failure

virsh domstate ep11-broken01 --reason

2. Identify the first causal error across virsh, journal, and QEMU logs

virsh domblklist ep11-broken01 --details

3. Repair only the bad definition or path

journalctl -u libvirtd --since '10 minutes ago'

4. Start the original guest and verify both disks and networks

virsh start ep11-broken01

Finished state

Demo-ubuntu01 runs on host02 with its original identity, two writable disks, and two networks. The public scripts contain no private keys, passwords, or tokens. Review names, addresses, paths, ownership, backups, quorum, and fencing for your own environment before running them.

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