[ANNOUNCE] kubelet under rkt and deprecation of /usr/bin/kubelet in CoreOS

[pb]

Hello,

For the last few months we have been shipping the kubelet, the Kubernetes control agent, inside of the CoreOS Linux alpha and beta releases. However, this has proved difficult as Kubernetes is a fast moving project and API compatibility between this agent (kubelet) and its control plane (kubernetes) has made it difficult for users to upgrade CoreOS and the kubelet in lock step.

As a result, we will begin removing the kubelet binary and service file from the CoreOS image in roughly two months (around June, 2016). We ask that users of the kubelet binary move to using the kubelet shipped as a container.

As of CoreOS release v962.0.0, we ship an executable script, /usr/lib/coreos/kubelet-wrapper, that will function just like a kubelet-binary but, download and launch the kubelet as container running under rkt fly. Use of the script only requires setting the KUBELET_VERSION environment variable to a tag published here: https://quay.io/repository/coreos/hyperkube?tab=tags.  For more information see the documentation here: https://coreos.com/kubernetes/docs/latest/kubelet-wrapper.html. We’ve just released v0.6.0 of our coreos-kubernetes repo which supports creation of Kubernetes v1.2 clusters.

Feel free to ask us questions here or in IRC channel #coreos on freenode.

Thanks,

The CoreOS OS Team