Since you can mount ISO files as a “CDRom Device” inside VM’s, the common question that normally will come up is, “How do I make ISO files from my existing CD’s?” There are a number of ways to do this however you can use ESX to make the ISO images and then store them either locally on the ESX server or on a SAN attached VMFS. I would recommend putting them on a SAN attached VMFS volume so all of your ESX servers can access them.
Connect via SSH and Make ISO
The first step is to put the CD in the physical CD reader on the ESX hardware.
Now, SSH into the ESX server (as described under "Connecting via SSH/CLI" in this guide).
Next, type in the following command (also shown in the screenshot):
dd if=/dev/cdrom of=/vmfs/volumes/vmfs_name/filename_for_cd.iso
Replace "vmfs_name" with the actual name of your VMFS datastore.
Replace "filename_for_cd" with the actual name that you want to use for the ISO you are creating.
Browse for ISO
Now go to that directory where you pointed the “of” (or output file) and you should be able to see your ISO image as shown in the screenshot. Now you can use this ISO file as a CD-ROM device in your Virtual Machine by editing the properties of the virtual machine and pointing the CD to the datastore ISO you created.