is there a way to create an ISO image of my virtual machine directly from Virtualbox on which it is installed ?
I have not seen any tools that will allow for the creation of ISOs of VMs from virtualbox. You can however move a vdi image onto a thumb drive and move it to another system running virtualbox. You can create disk images of the VMs using bit copying tools like "dd" or a GUI based disk imager. ISOs are normally CD images the boots a system for installation or administrative uses. Did not see an option to do this in virtualbox for linux.