Reasoning

Why build kini?

kind is commonly used in the ClusterAPI world in order to bring up management clusters for development purposes. kind requires a Docker runtime to be installed on the machine, in order to launch privileged containers and start up a local Kubernetes cluster.

However, the most common configuration for single node Docker and Incus configurations comes with a few caveats:

• Incus will usually configure a incusbr0 local bridge, which is used by instances.
• Docker will configure a separate dockerbr0 local bridge, and by default aggressively adjust iptables rules.

In this mode, the Docker containers (kind-control-plane) and the CAPN machines are in different networks, and the default iptables rules do not allow them to communicate with each other.

Motivated by the fact that recent Incus versions have added support for OCI containers, kini implements a shim layer between kind and the Docker daemon. As such, rather than creating a Docker container, it will instead launch an Incus container, using the same storage and networking as other machines.