Change cdrom

Qemu provides a way to change iso in the cdrom via the monitor interface.

QEMU 0.10.5 monitor - type 'help' for more information
(qemu)

The commands you'll want to use, info block, eject, and change. First we need to determine which block device is the cdrom you are interested in. Issue the info block command and look for cdrom devices.

(qemu) info block
ide0-hd0: type=hd removable=0 file=/dev/null ro=0 drv=host_device encrypted=0
ide1-cd0: type=cdrom removable=1 locked=0 [not inserted]
floppy0: type=floppy removable=1 locked=0 [not inserted]
sd0: type=floppy removable=1 locked=0 [not inserted]

ide1-cd0 is the only cdrom device in this example and there isn't any media inserted. To change the cdrom, we issue the change command supplying the device name (ide1-cd0) and the path to the new iso file.

(qemu) change ide1-cd0 /tmp/dsl-4.4.10.iso 
(qemu) info block
ide0-hd0: type=hd removable=0 file=/dev/null ro=0 drv=host_device encrypted=0
ide1-cd0: type=cdrom removable=1 locked=0 file=/tmp/dsl-4.4.10.iso ro=0  drv=raw encrypted=0
floppy0: type=floppy removable=1 locked=0 [not inserted]
sd0: type=floppy removable=1 locked=0 [not inserted]
(qemu) 

In case you already have a cdrom in the drive you need to eject the current iso first before issuing the change command. The eject command takes the name of the cdrom block device.

(qemu) eject ide1-cd0
(qemu) info block
ide0-hd0: type=hd removable=0 file=/dev/null ro=0 drv=host_device encrypted=0
ide1-cd0: type=cdrom removable=1 locked=0 [not inserted]
floppy0: type=floppy removable=1 locked=0 [not inserted]
sd0: type=floppy removable=1 locked=0 [not inserted]
(qemu) change ide1-cd0 /tmp/fedora11.iso 
(qemu) info block
ide0-hd0: type=hd removable=0 file=/dev/null ro=0 drv=host_device encrypted=0
ide1-cd0: type=cdrom removable=1 locked=0 file=/tmp/fedora11.iso ro=0 drv=raw  encrypted=0
floppy0: type=floppy removable=1 locked=0 [not inserted]
sd0: type=floppy removable=1 locked=0 [not inserted]