* Remove variables defined in download role. Fixes #3799

* Cleanup some more variables

* Fix bad templating

* Minor fix

* Add dashboard to download role. Fixes #3736

* Set configure-cloud-routes=false as default if no network plugin is used

As configure-cloud-routes default value is `true`, so it need to be set to `false` when not required to avoid error messages like:
"Couldn't reconcile node routes: error listing routes: unable to find route table for AWS cluster" 
on, for example, AWS installations that don't use cloud native routing.

* Update kube-controller-manager.manifest.j2

remove extra spaces

Upstream Changes:

  - ingress-nginx 0.21.0 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.21.0)

Our Changes:

  - Sync templates with upstream changes
  - Remove --default-backend-service requirement. Use the flag only for custom default backends

This takes care of a few arbitrary use cases that may require custom mounts
inside of apiserver, controller manager, or scheduler.

Introduced variable node_taints which can be set in inventory for
specific hosts or in group_vars, which generates --register-with-taints
command line argument for kubelet.

Introduced variable `ingress_nginx_tolerations` to set custom
tolerations for Ingress nginx daemonset, to be able to schedule
ingress-nginx on dedicated nodes with taints.

* Update defaults to match k8s 1.12 suggestions

* Test if Netchecker works with node ip instead of localhost

* Update defaults to ipvs and coredns

* Update defaults for kube_apiserver_insecure_port

* Update main.yaml

This feature was removed by PR#3061. But change flag manage_docker to deploy_container_engine.

When `ansible_user` is not root, using `-b` option.
And with `download_run_once` and `download_localhost` set `true`.

Ansible will executes `container_download | upload container images to nodes` task.

It uses rsync to upload images to `/tmp/release/container/`, but the
`container` directory owned by `root`.

Now the `kubespray-aws-inventory.py` script always set a node_labels key
to ansible_host.

When AWS instance did not set property labels, it would be an empty
string.

The TASK `Write kubelet config file (kubeadm or non-kubeadm)` will
failed with a msg:

`AnsibleUndefinedVariable: 'unicode object' has no attribute 'items'`.

* Support Metrics Server as addon (#3560).

* Update metrics server v0.3.1.

* Add metrics server test.

* Replace metrics server manifests with kubernetes/cluster/addons's.

* Modify metrics server manifests for kubespray.

* Follow PR#3558 node label node-role.kubernetes.io/master change

* Fix metrics server parameters base_metrics_server_... to metrics_server_...

* Fix too hard corded metrics_server_memory_per_node

* Add configurable insecure tls for metrics-apiservice

* Downloadable addon-resizer and extract parameter as variables

* Remove metrics server version from deployment name

* Metrics Server work when all masters has node role

* Download metrics-server and add-resizer container only on master

* ServiceAccount and ConfigMap is separated and fix application name

* Remove old metrics server clusterrole template

* Fix addon-resizer image specify

* Make InternalIP default for metrics_server_kubelet_preferred_address_types

Make InternalIP default because multiple preferrred address types does not work.

* Switch to kubeadm deployment mode

Discuss:https://github.com/kubernetes-incubator/kubespray/issues/3301

* Add non-kubeadm upgrage to kubeadm cluster

Upstream Changes:

-   cert-manager 0.5.2 (https://github.com/jetstack/cert-manager/releases/tag/v0.5.2)

Our Changes:

-   Templates sync with upstream manifests

* Add resource-container flag to kube-proxy manifest

* add resourceContainer: "" to kubeadm kube-proxy configs

* Fix DNS Autoscaler for coredns_dual deployment

* Fix templating

* Fix templating again

comparison that happens during `TASK [kubernetes-apps/ansible : Kubernetes Apps | Lay Down CoreDNS Template]` where the `dns-autoscaler` template is deployed causes coredns to fail deployment.  The error is caused by the variable `dns_prevent_single_point_failure` where an integer is being compared with a string. The resulting error:

```bash
'>' not supported between instances of 'int' and 'str'
```

prevents successful deployment of CoreDNS.  

The change makes the comparison happen between integers and allows CoreDNS to succeed.

Due to suboptimal external loadbalancer configs, the LoadBalancer
might point to a downed kube-apiserver that is not set up yet.