Implements virtual media (CD/DVD) boot using Nova rescue mode
as an alternative to volume rebuild based approach. This enables
virtual media on older clouds and works around OVMF firmware
issues with volume-backed media. (OVMF can be picky about booting
ISO's, on some 'sata' bus works, other OVMF need 'scsi' bus...)
Key changes:
- Insert image uploads ISO to Glance, stores in PersistentDict
- Boot device 'Cd' sets rescue boot mode for next power cycle
- Power on triggers rescue with ISO image (async handling)
- Power off performs unrescue then stop operations
- Eject deletes ISO from Glance and clears state
**Refactors** existing vmedia to use PersistentDict instead of
Nova metadata for state tracking. Users requiring state persistence
across service restarts must configure SUSHY_EMULATOR_STATE_DIR.
Added unit tests and documentation covering configuration, workflows,
and limitations.
Assisted-By: Claude (claude-4.5-sonnet)
Change-Id: I67beaf4414980525e10344ed0e6e3a1bbd6492d4
Signed-off-by: Harald Jensås <hjensas@redhat.com>
Harald Jensås
d5f8532128