Add Docker Engine as container runtime

Mention that the support via Dockershim is deprecated.

Co-Authored-By: Rey Lejano <[email protected]>

Author: Tim Bannister

content/en/docs/setup/production-environment/container-runtimes.md

@@ -15,11 +15,18 @@ what is involved and describes related tasks for setting up nodes.
 
 <!-- body -->
 
+Kubernetes {{< skew currentVersion >}} requires that you use a runtime that
+conforms with the 
+{{< glossary_tooltip term_id="cri" text="Container Runtime Interface">}} (CRI).
+
+See [CRI version support](#cri-versions) for more information.
+
 This page lists details for using several common container runtimes with
 Kubernetes, on Linux:
 
 - [containerd](#containerd)
 - [CRI-O](#cri-o)
+- [Docker Engine](#docker)
 - [Mirantis Container Runtime](#mcr)
 
 {{< note >}}
@@ -94,10 +101,19 @@ In order to use it, cgroup v2 must be supported by the CRI runtime as well.
 Follow this [Migration guide](/docs/tasks/administer-cluster/kubeadm/configure-cgroup-driver/)
 if you wish to migrate to the `systemd` cgroup driver in existing kubeadm managed clusters.
 
+## CRI version support {#cri-versions}
+
+Your container runtime must support at least v1alpha2 of the container runtime interface.
+
+Kubernetes {{< skew currentVersion >}}  defaults to using v1 of the CRI API.
+If a container runtime does not support the v1 API, the kubelet falls back to
+using the (deprecated) v1alpha2 API instead.
+
 ## Container runtimes
 
 {{% thirdparty-content %}}
 
+
 ### containerd
 
 This section contains the necessary steps to use containerd as CRI runtime.
@@ -394,6 +410,24 @@ Please also note the changed `conmon_cgroup`, which has to be set to the value
 cgroup driver configuration of the kubelet (usually done via kubeadm) and CRI-O
 in sync.
 
+### Docker Engine {#docker}
+
+Docker Engine is the container runtime that started it all. Formerly known just as Docker,
+this container runtime is available in various forms.
+[Install Docker Engine](https://docs.docker.com/engine/install/) explains your options
+for installing this runtime.
+
+Docker Engine is directly compatible with Kubernetes {{< skew currentVersion >}}, using the deprecated `dockershim` component. For more information
+and context, see the [Dockershim deprecation FAQ](/dockershim).
+
+You can also find third-party adapters that let you use Docker Engine with Kubernetes
+through the supported {{< glossary_tooltip term_id="cri" text="Container Runtime Interface">}}
+(CRI).
+
+The following CRI adaptors are designed to work with Docker Engine:
+
+- [`cri-dockerd`](https://github.com/Mirantis/cri-dockerd) from Mirantis
+
 ### Mirantis Container Runtime {#mcr}
 
 [Mirantis Container Runtime](https://docs.mirantis.com/mcr/20.10/overview.html) (MCR) is a commercially