Seperate loop and plugin control in the kube-controller-manager.
Adding an "--external-plugin" flag to specify a plugin to load when
cloud-provider is set to "external". Flag has no effect currently
when the cloud-provider is not set to external. The expectation is
that the cloud provider and external plugin flags would go away once
all cloud providers are on stage 2 cloud-controller-manager solutions.
Managing the control loops more directly based on start up flags.
Addressing issue brought up by @wlan0
Switched to using the main node controller in CCM.
Changes to enable full NodeController to start in CCM.
Fix related tests.
Unifying some common code between KCM and CCM.
Fix related tests and comments.
Folded in feedback from @jhorwit2 and @wlan0
Automatic merge from submit-queue
Remove the kube-discovery binary from the tree
**What this PR does / why we need it**:
kube-discovery was a temporary solution to implementing proposal: https://github.com/kubernetes/community/blob/master/contributors/design-proposals/bootstrap-discovery.md
However, this functionality is now gonna be implemented in the core for v1.6 and will fully replace kube-discovery:
- https://github.com/kubernetes/kubernetes/pull/36101
- https://github.com/kubernetes/kubernetes/pull/41281
- https://github.com/kubernetes/kubernetes/pull/41417
So due to that `kube-discovery` isn't used in any v1.6 code, it should be removed.
The image `gcr.io/google_containers/kube-discovery-${ARCH}:1.0` should and will continue to exist so kubeadm <= v1.5 continues to work.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
Remove cmd/kube-discovery from the tree since it's not necessary anymore
```
@jbeda @dgoodwin @mikedanese @dmmcquay @lukemarsden @errordeveloper @pires
This adds a new stand-alone certificates controller for use on GKE. It
allows calling GKE to sign certificates instead of requiring the CA
private key locally.
It does not aim for 100% feature parity with kube-controller-manager
yet, so for instance, leader election support is omitted.