Ability to create dynamic HA clusters with kubeadm

[luxas]

Feature Description

• One-line feature description (can be used as a release note): Dynamic HA clusters can easily be created with the kubeadm tool using exactly the same kubeadm init and kubeadm join commands the users are familiar with.
• Primary contact (assignee): @luxas @timothysc
• Responsible SIGs: @kubernetes/sig-cluster-lifecycle-feature-requests
• Design proposal link (community repo): https://docs.google.com/document/d/1P3oUJ_kdaRSTlGONujadGBpYegjn4RjBNZLHZ4zU7lI/edit#
• Related KEPS:
  https://github.com/kubernetes/enhancements/blob/master/keps/sig-cluster-lifecycle/kubeadm/0015-kubeadm-join-control-plane.md
  https://github.com/kubernetes/enhancements/blob/master/keps/sig-cluster-lifecycle/kubeadm/20190122-Certificates-copy-for-kubeadm-join--control-plane.md
• Reviewer(s) - (for LGTM) recommend having 2+ reviewers (at least one from code-area OWNERS file) agreed to review. Reviewers from multiple companies preferred: @fabriziopandini @timothysc
• Approver (likely from SIG/area to which feature belongs): @fabriziopandini @timothysc
• Feature target (which target equals to which milestone):
  • Alpha release target (x.y): v1.9
  • Beta release target (x.y): v1.15
  • Stable release target (x.y): v1.24

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Edit by @spiffxp:

Per #357 (comment) we should consider kicking this out of of v1.14 and using a separate tracking issue for the actual KEP being implemented this cycle: 20190122-Certificates-copy-for-kubeadm-join--control-plane.md

[luxas]

Hoping to get an alpha implementation of this in v1.8. Might or might not work out. At least a ready design doc should be ready at the end of the v1.8 cycle.

[luxas]

@kubernetes/sig-cluster-lifecycle-feature-requests I moved this to next-milestone as no code for this is shipping in v1.8, only design

[luxas]

Targeting alpha in v1.9