Butter Cloud

A basic cloud provider focused on ease of use above all else.

Status

This README is just describing what the project goals are, nothing is really implemented yet.

Goal

To make it easy to take a set of normal personal machines on any network and convert them into a "cloud" with an API that allows dynamic creation of private networks and virtual machines on demand.

This is similar in spirit to https://www.openstack.org/, but is an experiment to see what happens if we are willing to sacrifice everything else (besides security and safety) for simplicity ease of use above all else.

For example, if there is a way to improve performance, but it makes things harder to understand or use, then the idea is to ignore that and keep it simple. Maybe this can become a good teaching tool, but also it can be a test to see how far we can take that idea.

Implementation

The definition of "cloud" here is purposely limited to just creating private networks and virtual machines.

For the private networks, the idea is to use wireguard to create a VPN, and then have all the guest VMs join that VPN. Specifically, this will mean tunneling something that can operate at layer 2 and be connected to the guest VMs through wireguard. See this post.

For VMs, anything that makes it easy at first would be good, probably backed by libvirt.

So far, a proof of concept has been done with gretun, wireguard, and vagrant running libvirt. See this diagram:

• eth0 (guest) is the only interface the guest VM sees. The proof of concept uses vagrant.
• brtun is an ethernet bridge, which can be used to put two ethernet devices on the same network. See this paper.
• gretun is a virtual ethernet device created using Generic Routing Encapsulation.
• wg0 is the wireguard VPN interface that encrypts traffic to the other end of the connection.
• eth0 (host) is the ethernet device on the host that is actually connected to the internet.

The end result of all this is that the ethernet device on the guest is "plugged in" to the ethernet bridge brtun, and gretun is also plugged into that bridge. Since gretun is just an ethernet device, the connection from one end to the other is similar to just having an ethernet cable between the two hosts. However, instead of an ethernet cable, this is a virtual ethernet device that uses wg0 to send packets to the other end. wg0 in turn, is a VPN interface rather than a normal network interface, that encrypts the packets before sending them on the way over the host ethernet interface out to the internet.

Then, the packets are recieved on the other side, and the whole process is reversed.