vmrc-faq.txt

vmrc Frequently Asked Questions

Q: Why is vmrc written in /bin/sh ?

A: Many reasons:

   * /bin/sh is fast to develop with and execute
   * /bin/sh is largely portable between operating systems
   * All system preparation and execution tasks are executed in the shell

   ( Library exposure of all kernel module, networking and hypervisor features
     would be a elegant but would compromise portability and slow development )


Q: Why an rc script?

A: This is how Unix systems launch services and a virtual machine is often
   desired at boot time. An rc script can also be incorporated into any
   system orchestration system that can launch a service such as a web server.

   Yes, it is an official practice to add arguments to an rc.d script:
https://www.freebsd.org/doc/en_US.ISO8859-1/articles/rc-scripting/rcng-args.html

Q: Why support multiple hypervisors/emulators?

A: Most hypervisors and emulators share similar qualities:

   * A bootable block device or "diskless" directory
   * A RAM allocation, unless a "jail"
   * Some amount of network configuration

   Given this fact, virtual machines are remarkably portable and vmrc has been
   used to boot a hardware OS installation under bhyve, Xen, QEMU and the
   original host hardware. Most operating systems do not care where they are
   booted.

   Also, when working with a new hypervisor like bhyve, you never know if your
   hypervisor or virtual machine is to blame for a boot failure and the ability
   to validate (or preconfigure) a virtual machine is very helpful.


Q: What hypervisors and emulators does vmrc support?

A: bhyve, Xen and QEMU on FreeBSD


Q: What hypervisors and emulators is vmrc planned to support?

A: jail(8), VirtualBox, Bochs (supports single stepping!), GXemul, simh and
   QEMU ARM64.


Bugs, questions and/or comments:
Michael Dexter <editor@callfortesting.org>