Rancher supports Docker 18.06.2
As Docker has also patched 18.06.2, Rancher will also be supporting Docker 18.06.2 for Rancher v2.1.6, v2.0.11 and v1.6.26. Please refer to the Rancher Support Matrix to see which versions of Rancher, OS, K8s, and Docker are currently supported .
We recommend upgrading Docker to either 18.06.2 or 18.09.2 for all nodes/hosts in Rancher.
Provisioning Clusters in Rancher with Docker 18.06.2 or Docker 18.09.2
If you are launching clusters that have Rancher launching and managing Kubernetes, in the Kubernetes options for Docker versions on nodes, you will need to keep the default of Allow unsupported versions in order for the Kubernetes cluster to provision correctly with Docker 18.06.2 or Docker 18.09.2. The next patch versions of Rancher will be updated so this will not be required.
RKE v0.1.15 with Docker 18.06.2 and Docker 18.09.2
The current version of RKE (v0.1.15) will not launch clusters with Docker 18.06.2 or Docker 18.09.2 unless you specifically ignore the Docker version check. Per the instructions, you can disable this supported Docker verification in either your cluster.yml or you can temporarily disable it whenever you run rke up by passing in --ignore-docker-version.
Rancher is planning on shipping RKE v0.1.16 to address this issue by February 15.