Live Migration¶

What "live migration" means here¶

A real live migration keeps the guest running while its memory and disk state move to another hypervisor, with a short, bounded pause at the switchover. It is not "a migration that happens to be fast", and it is not a cold migration with a smaller stop window.

The panel implements the orchestration and capability gating for live migration. It emits the semantic MIGRATION_LIVE task; the actual live move is performed by the agent/driver.

Modes¶

Mode	Behaviour
`LIVE_REQUIRED`	Fails preflight if the target does not advertise `live_migration`. Never downgrades to cold.
`LIVE_IF_POSSIBLE`	Uses live when the target supports it, otherwise a warning and a cold move is planned.
`AUTO`	Chooses live when possible and policy allows, otherwise cold.
`COLD`	Never live.

A LIVE_REQUIRED request against a non-live target produces a PROVIDER_CAPABILITY_MISSING blocker and eligible=false.

Restrictions¶

The target must advertise the live_migration capability (a panel-trusted field synced from the agent).
Host-bound resources cannot live-migrate: CPU host-passthrough, GPU/PCI passthrough and (by default) strict NUMA/hugepage/hardware requirements are hard blockers.
A same-IP cross-node move is not atomic: the source route is removed before the target route is applied, so a brief network interruption is recorded.
Live migration of a guest with local-only storage is not possible without a disk copy; the storage plan decides whether a copy is required.

Policy¶

MigrationPolicy.allow_live gates whether live modes are offered at all. The live_timeout bounds a live attempt. The panel reports the requested downtime posture; the orchestrator confirms capability at execute time.

Honesty¶

Mock-tested: capability gating, LIVE_REQUIRED hard-fail, no silent downgrade, warnings separated from blockers, downtime class reporting.
NOT TESTED on hardware: no real QEMU/libvirt live migration has been performed or measured. There are no downtime, throughput or convergence claims. Treat live migration as capability-gated but hardware-unproven.