Virtual computing instance based system to support union mount on a platform

A computer system comprising:

• at least one processor;
• and
• a memory coupled to the at least one processor, the memory and the at least one processor being configured to:
• run a virtual machine on a host operating system of a computing device, wherein the host operating system lacks a union mount capability;
• share a first folder and a second folder on the host operating system with a guest operating system of the virtual machine that has a union mount capability, such that a shared first folder and a shared second folder corresponding to the first folder and the second folder, respectively, appear to be present on the guest operating system of the virtual machine;
• perform in the guest operating system of the virtual machine a union mount of the shared first folder and the shared second folder to form a union mount folder;
• reverse-share the union mount folder on the guest operating system with the host operating system, such that a shared union mount folder corresponding to the union mount folder appears to be present on the host operating system, wherein the first folder is a read-only folder and the second folder is a writable folder, and write operations to the shared union mount folder are reflected in the second folder and not in the first folder;
• and
• upon completion of reverse-sharing of the union mount folder with the host operating system, shut down the virtual machine, thereby disabling sharing of the first folder with the shared first folder and the second folder with the shared second folder.

A non-transient computer-readable medium containing instructions executable in a computer system, where the instructions when executed in the computer system cause the computer system to carry out a method of performing a union mount of two folders, the method comprising:

• running a virtual machine on a hypervisor executing on a host operating system of the computer system, wherein the host operating system lacks a union mount capability;
• sharing a first folder and a second folder on the host operating system with a guest operating system of the virtual machine that has a union mount capability, such that a shared first folder and a shared second folder corresponding to the first folder and the second folder, respectively, appear to be present on the guest operating system of the virtual machine;
• performing in the guest operating system of the virtual machine a union mount of the shared first folder and the shared second folder to form a union mount folder;
• reverse-sharing the union mount folder on the guest operating system with the host operating system, such that a shared union mount folder corresponding to the union mount folder appears to be present on the host operating system, wherein the first folder is a read-only folder and the second folder is a writable folder, and write operations to the shared union mount folder are reflected in the second folder and not in the first folder;
• and
• upon completion of said reverse-sharing the union mount folder with the host operating system, shutting down the virtual machine, thereby disabling sharing of the first folder with the shared first folder and the second folder with the shared second folder.