The MCS should detect a pool’s desired layered OS image so that brand-new nodes pivot to the layered image during first boot and require only one reboot.

• When a pool is opted into image mode and has a mosc with a ready image and a matching, successful mosb for the pool’s current/next MC, the MCS injects that image (spec.osImageURL) into the MC before encapsulation.

• The encapsulated MC is written to disk on first boot; mcd-firstboot reads it and pivots immediately to the desired image, achieving a single reboot path.

• If image mode isn’t ready (no mosc, no image in status, or the mosb is not successful), the MCS serves the standard MC (no osImageURL), and behavior falls back to today’s flow (no premature pivot, no surprises).

Acceptance criteria

• The Ignition payload includes an encapsulated MachineConfig whose spec.osImageURL equals the MOSC/MOSB image.

• On first boot, mcd-firstboot pivots to that image and reboots once.

• After the reboot, the node reports the expected currentImage annotation and matches the image digest from MOSC/MOSB.