libvirt provider: firectl

[taqtiqa-mark]

This question arose after reading issue #20:

If I understand firectl correctly it appears that firectl is more natural fit as a libvirt provider.
Some benefit would come from that: Such as immediately being available to the world of applications using libvirt, one such sizeable group are Vagrant developers via the Vagrant libvirt provider.

Has libvirt been considered and rejected?

[nmeyerhans]

Hi @taqtiqa-mark. It hasn't been considered at all, as far as I'm aware. It's an interesting idea, and you may be right that it's a more natural fit for libvirt than standalone firecracker would be.

On the other hand, is it possible that Firecracker's changes to allow a MicroVM configuration to be passed via a configuration file will simplify libvirt integration without requiring firectl?

[taqtiqa-mark]

On the other hand, is it possible that Firecracker's changes to allow a MicroVM configuration to be passed via a configuration file will simplify libvirt integration without requiring firectl?

I don't know any of the firecracker team, but judging from the design of firecracker I'd guess libvirt is close to a nightmare for them ;)

For example the configuration by file is all XML - I'll spare everyone the rant.
It's also clear the libvirt scope if much larger than firecracker's.

Consequently, it is a non-trivial exercise and question to work out what is a firecracker configuration in terms of the libvirt model of VM's. To take an example, VM storage: it isn't immediately obvious what the firectl configuration for storage would be in terms of libvirt model.

Perhaps one possibility toward convergence is for firectl to consume/generate a YAML configuration file format that can be exported to libvirt's schema?

Example:
libvirt's :

<domain type='kvm' id='1'>
  <name>MyGuest</name>
  <uuid>4dea22b3-1d52-d8f3-2516-782e98ab3fa0</uuid>
  <genid>43dc0cf8-809b-4adb-9bea-a9abb5f3d90e</genid>
  <title>A short description - title - of the domain</title>
  <description>Some human readable description</description>
  <metadata>

  </metadata>

YAML:

domain:
  name: MyGuest
  uuid: 4dea22b3-1d52-d8f3-2516-782e98ab3fa0
  genid: 43dc0cf8-809b-4adb-9bea-a9abb5f3d90e
  title: A short description - title - of the domain
  description: Some human readable description
  metadata: ''
  _type: kvm
  _id: '1'

A positive of this would be that firectl's configuration items, and documented meanings are already defined - that subset of libvirt.
A negative of this would be that firectl's configuration items, and documented meanings are already defined - that subset of libvirt.

[taqtiqa-mark]

A word on context: I came across firectl when looking to see what would be the best way to add a Vagrant provider for firecracker. Initially I thought Ignite, but I'm now think that would not be sustainable. Firectl seemed like the next natural avenue.

On reflection I'm starting to think either wait for a firecracker provider for libvirt, or use firecracker directly.

Nonetheless, it would seem there is some long term benefit for firectl users if they know they can export libvirt compatible configurations.