You can do that kind of bootstrap without fleet. Just use ignition or cloud-config with the right systemd units and a bunch of fixed IP addresses. I think the CoreOS folks worked on a number of ways to simplify and automate bootstrapping of the Kubernetes control plane, so they saw fleet as redundant now. Besides, it took a long time for it to get something resembling a mechanism that updates units in the cluster.
That said, being a lower level tool as you point out, it can be useful during e.g. troubleshooting. Imagine the case where `fleetctl list-machines` returns more nodes than `kubectl get nodes`.
with fleet you could have a single kubernetes master that would've been started on another node, as soon as one node would go down. that won't work with just systemd units.
That said, being a lower level tool as you point out, it can be useful during e.g. troubleshooting. Imagine the case where `fleetctl list-machines` returns more nodes than `kubectl get nodes`.