http://support.citrix.com/servlet/KbServlet/download/32303-102-691296/guest.pdf chapter 5.5
2. Mount the image onto the guest by running the command:
# mount -o ro,exec /dev/disk/by-label/XenServer\\x20Tools /mnt
If mounting the image fails, you can locate the image by running the following:
blkid -t LABEL=”XenServer Tools”
3. Execute the installation script as the root user:
4. Unmount the image from the guest by running the command:
# umount /mnt
5. If the kernel has been upgraded, or the VM was upgraded from a previous version, reboot the VM now.
CD-ROM drives and ISOs attached to Linux Virtual Machines appear as devices, such as /
dev/xvdd (or /dev/sdd in Ubuntu 10.10 and later) instead of as /dev/cdrom as you
might expect. This is because they are not true CD-ROM devices, but normal devices. When
the CD is ejected by either XenCenter or the CLI, it hot-unplugs the device from the VM and the
device disappears. This is different from Windows Virtual Machines, where the CD remains
in the VM in an empty state.