Note: kubernetes doesn't support newer docker versions ("Version 17.03 is recommended... Versions 17.06+ might work, but have not yet been tested and verified by the Kubernetes node team" cf. [Bootstrapping Clusters with kubeadm](https://kubernetes.io/docs/setup/independent/install-kubeadm/#installing-docker)). Among other things kubelet currently breaks on docker's non-standard version numbering (it no longer uses semantic versioning). To ensure auto-updates don't break your cluster look into e.g. yum versionlock plugin or apt pin).
Note: The list of validated [docker versions](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.12.md) was updated to 1.11.1, 1.12.1, 1.13.1, 17.03, 17.06, 17.09, 18.06. The kubelet might break on docker's non-standard version numbering (it no longer uses semantic versioning). To ensure auto-updates don't break your cluster look into e.g. yum versionlock plugin or apt pin).
Note 2: rkt support as docker alternative is limited to control plane (etcd and
Note 2: rkt support as docker alternative is limited to control plane (etcd and
kubelet). Docker is still used for Kubernetes cluster workloads and network
kubelet). Docker is still used for Kubernetes cluster workloads and network