* Adds support for Multus (multiple interfaces) CNI plugin

Multus is a latin word for "Multi". As the name suggests, it acts as a
Multi plugin in Kubernetes and provides multiple network interface
support in a pod. Multus uses the concept of invoking delegates by
grouping multiple plugins into delegates and invoking them in the
sequential order of the CNI configuration file provided in json format.

* Change CNI version (0.1.0->0.3.1) of Contiv to be compatible with Multus

* failed

* version_compare

* succeeded

* skipped

* success

* version_compare becomes version since ansible 2.5

* ansible minimal version updated in doc and spec

* last version_compare

* Automatically infer bootstrap_os

* Rename bootstrap os to os_family

* Fix bootstrap_os/ubuntu idempotency

* Update bastion role

* move container_engine in sub-roles

* requires ansible 2.5

* ubuntu18 as first CI job

* 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

https://github.com/kubernetes/kubernetes/issues/69214

- 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

* 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

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

* calico upgrade to v3

* update calico_rr version

* add missing file

* change contents of main.yml as it was left old version

* enable network policy by default

* remove unneeded task

* Fix kubelet calico settings

* fix when statement

* switch back to node-kubeconfig.yaml

Upgrade Kubernetes to V1.11.2
The kubeadm configuration file version has been upgraded from v1alpha1 to v1alpha2
Add bootstrap kubeadm-config.yaml with external etcd

Use helm install or support in future

* Add tags for cert serial tasks

This will help facilitate tag-based deployment of specific components.

* fixup kubernetes node