[docker](https://www.docker.com/) v1.13.1 (see note)<br>
[docker](https://www.docker.com/) v1.13 (see note)<br>
[rkt](https://coreos.com/rkt/docs/latest/) v1.21.0 (see Note 2)<br>
Note: kubernetes doesn't support newer docker versions. 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).