Kubelet configuration available via machine configuration

[smira]

Kubelet command line flags are getting deprecated, and new way to use the config file.

Talos today accepts only extraArgs, so we need a better way to fine-tune kubelet.

We don't want to import whole KubeletConfig as a Go structure into the machine configuration as this will cause unnecessary dependency. We would rather present KubeletConfig as a map[string]interface{}, we skip any validation on Talos side, and simply unmarshal raw data into the KubeletConfig before starting the kubelet. Kubelet will validate its config and error out if it's invalid.

[sergelogvinov]

I think a few parameters Talos has to disable change.
like

authentication:
authorization:
staticPodPath:
port:
resolvConf:
systemReserved:
*cgroup*

[smira]

Machine Configuration

Validate that user kubelet configuration doesn't try to set values which are blacklisted (always set by Talos).

Controllers

Kubelet configuration controller should prepare defaults (like it does today) and merges them with the user-supplied kubelet configuration building the final kubelet configuration.

node-ip

If the kubelet configuration specifies nodeIP, automatic node IP configuration on Talos should be disabled.