* Update pre-install verify settings with network checks and etc.

* Remove upstream dns server check. It's bogus

* Ability to specify ssl certificate duration and ssl key size - etcd/secrets

* Ability to specify ssl certificate duration and ssl key size - helm/contiv + fix contiv missing copy certs generation script

- Local Volume StorageClass configuration is now manged by `local_volume_provisioner_storage_classes`, a list of maps that specifies local storage classes with `name` `host_dir` and `mount_dir` keys per entry
- Tasks and templates updated to loop through local volume storage classes
- Previous defaults for path/class names were not changed
- Fixed an issue where a `kubernetes/preinstall` was creating directories inconsistently with the `kubernetes-apps/external_provisioner/local_volume_provisioner` task

* Upgrade kubernetes to v1.12.0

Use kubeadm v1alpha3 config

* Upgrade coredns and etcd

* Upgrage docker to 18.06

* Fix the jinja expression for openstack_tenant_id

OS_PROJECT_ID is obsolete in keystone v3 and jinja expression
doesn't set openstack_tenant_id as expected because of
undefined env var. Fixed the expression.

* Fix the dic iteration method in the kubelet template

Kubelet template rendering errors when additional Node lables are
added and using Python3. Update the method to be compatible to both
python2/3

Node lables doesn't work

* Better fix for openstack cinder zone issue[1][2]
using ignore-volume-az option[3].
[1]: https://github.com/kubernetes-incubator/kubespray/pull/2155
[2]: https://github.com/kubernetes-incubator/kubespray/pull/2346
[3]: https://github.com/kubernetes/kubernetes/pull/53523

* Remove kube-scheduler-policy.yaml

* Changes to assign pod priority to kube components.

* Removed the boolean flag pod_priority_assignment

* Created new priorityclass k8s-cluster-critical

* Created new priorityclass k8s-cluster-critical

* Fixed the trailing spaces

* Fixed the trailing spaces

* Added kube version check while creating Priority Class k8s-cluster-critical

* Moved k8s-cluster-critical.yml

* Moved k8s-cluster-critical.yml to kube_config_dir

* Support for AWS cloud-config

* Update docs

* Fix version incompatibilities

* Do not use shorthand `default`

* Add new cloud config variable, roleArn

Move kube_kubeadm_controller_extra_args to controllerManagerExtraArgs section. It was placed in controllerManagerExtraVolumes

https://kubernetes.io/blog/2018/07/11/dynamic-kubelet-configuration/

https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1alpha2#JoinConfiguration