Add enable_cri_dockerd parameter

[dje4om]

Hi,

Refered to issue #325

Here is some outputs from my dev env

env var is well defined to the kubelet container, on dev node:

docker exec kubelet env                                                                                                                                                                                                                                                          

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
HOSTNAME=rke01
RKE_KUBELET_CRIDOCKERD=true
HOME=/root

kubelet args are also well defined

--container-runtime-endpoint=/var/run/dockershim.sock --container-runtime=remote

test is already ensured by rke if we tried an older version than kubernetes 1.21 :

rke_cluster.lab: Refreshing state... [id=f8cc1f51-5939-47b9-acc3-7baa527640c2]
local_file.kubeconfig_yaml: Refreshing state... [id=0b42f3ae3e24322d5cc8d646272f57196e001621]

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place

Terraform will perform the following actions:

  # rke_cluster.lab will be updated in-place
  ~ resource "rke_cluster" "lab" {
      ~ enable_cri_dockerd        = false -> true
        id                        = "f8cc1f51-5939-47b9-acc3-7baa527640c2"
        # (25 unchanged attributes hidden)

        # (1 unchanged block hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

rke_cluster.lab: Modifying... [id=f8cc1f51-5939-47b9-acc3-7baa527640c2]
╷
│ Error:
│ ============= RKE outputs ==============
│ time="2022-03-30T23:58:53+02:00" level=info msg="Updating RKE cluster..."
│ time="2022-03-30T23:58:53+02:00" level=info msg="Initiating Kubernetes cluster"
│
│ Failed initializing cluster err:Failed to validate cluster: Enabling cri-dockerd for cluster version [v1.20.13-rancher1-1] is not supported
│ ========================================
│
│
│   with rke_cluster.lab,
│   on lab.tf line 1, in resource "rke_cluster" "lab":
│    1: resource "rke_cluster" "lab" {
│
╵

[HarrisonWAffel]

This LGTM, but ill give final say to my colleague @annablender, as she has more experience with this repository

[tsde]

I think it is an important PR as Kubernetes 1.24 is now out and support for docker is dropped starting from this version. Having this merged along with #340 would be neat.

[a-blender]

I want to note the rancher docs where this field is listed as supported. The enable_cri_docker field also needs to be added to the RKE config tests in terraform. Otherwise, LGTM

DNM - pending 2.6.5 Terraform release.

[a-blender]

Terraform RKE v1.3.1 patch is released and sufficient smoke testing has been done to verify an RKE all role cluster with cri_dockerd_enable works as expected. Ok to merge.

[dje4om]

Hi, change has been done, thx for the review