Migration preflight and compatibility contract

Migration is a compatibility contract between source, destination, storage, network, firmware, CPU model, and libvirt/QEMU versions. Prove each boundary before moving memory.

Host checks

virsh -c qemu+ssh://target/system version
virsh -c qemu+ssh://target/system domcapabilities
virsh dumpxml guest01 --migratable > /root/guest01.migratable.xml
virsh domblklist guest01 --details
virsh domiflist guest01

Required decisions

• Is storage shared, copied, or replicated separately?
• Does the destination expose compatible CPU features and machine types?
• Are every network, secret, firmware, TPM, and host device dependency available?
• What is the abort threshold for downtime, dirty rate, and remaining data?
• Which host owns the guest if the management session fails?

Dry-run mindset

There is no substitute for testing the exact path with a representative workload. A successful empty-guest migration does not prove a write-heavy production guest will converge.