Juju 4.0 doesn't deploy the controller charm on microk8s

[Jordan Barrett]

If you bootstrap a controller with Juju 4.0 on microk8s, the controller model is empty:
------------------------------------------------
$ juju bootstrap microk8s c
$ juju switch controller
$ juju status

Model Controller Cloud/Region Version SLA Timestamp
Model "admin/controller" is empty.
controller c microk8s/localhost 4.0-beta1 unsupported 04:50:20Z
+ juju status --format json
------------------------------------------------

It should have the juju-controller charm deployed on bootstrap.

See https://chat.charmhub.io/charmhub/pl/66bgj7r1btbmjcynrw899xxdjr

[Ian Booth (wallyworld)]

ERROR cannot deploy controller application: cannot add controller application: cannot add application "controller": finding controller namespace with non legacy labels: Get "https://127.0.0.1:16443/api/v1/namespaces?labelSelector=model.juju.is%2Fname%3Dcontroller": dial tcp 127.0.0.1:16443: connect: connection refused
2023-10-26 03:57:09 DEBUG cmd supercommand.go:528 error stack:
Get "https://127.0.0.1:16443/api/v1/namespaces?labelSelector=model.juju.is%2Fname%3Dcontroller": dial tcp 127.0.0.1:16443: connect: connection refused
github.com/juju/juju/caas/kubernetes/provider.findControllerNamespace:195: finding controller namespace with non legacy labels
github.com/juju/juju/state/stateenvirons.(*environStatePolicy).ConstraintsValidator:119:
github.com/juju/juju/state.(*State).processCommonModelApplicationArgs:1469:
github.com/juju/juju/state.(*State).processCAASModelApplicationArgs:1581:
github.com/juju/juju/state.(*State).AddApplication:1272:
github.com/juju/juju/state.(*State).AddApplication:1272: cannot add application "controller"
github.com/juju/juju/cmd/jujud/agent.addControllerApplication:363:
github.com/juju/juju/cmd/jujud/agent.(*BootstrapCommand).deployControllerCharm:115: cannot add controller application
github.com/juju/juju/cmd/jujud/agent.(*BootstrapCommand).Run:447: cannot deploy controller application

[Ian Booth (wallyworld)]

We should make this a fatal error in juju 4.0. Previously it has been optional.

[Thomas Miller (tlmiller)]

PR: https://github.com/juju/juju/pull/16507