* Defaults for apiserver_loadbalancer_domain_name

When loadbalancer_apiserver is defined, use the
apiserver_loadbalancer_domain_name with a given default value.

Fix unconsistencies for checking if apiserver_loadbalancer_domain_name
is defined AND using it with a default value provided at once.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

* Define defaults for LB modes in common defaults

Adjust the defaults for apiserver_loadbalancer_domain_name and
loadbalancer_apiserver_localhost to come from a single source, which is
kubespray-defaults. Removes some confusion and simplefies the code.

Signed-off-by: Bogdan Dobrelya <bogdando@mail.ru>

Also disable oom killer on etcd

Now adding unjoined members to existing etcd cluster
occurs one at a time so that the cluster does not
lose quorum.

* Refactor downloads to use download role directly

Also disable fact delegation so download delegate works acros OSes.

* clean up bools and ansible_os_family conditionals

This reverts commit 4209f1cb.

* Security fixes for etcd

* Use certs when querying etcd

These facts can be generated in defaults with a performance
boost.

Also cleaned up duplicate etcd var names.

Fixes #1660

* Cleaning up cert checks for vault

* Removing all unnecessary etcd certs from each node

* Removing all unnecessary kube certs from each node

* kubeadm support

* move k8s master to a subtask
* disable k8s secrets when using kubeadm
* fix etcd cert serial var
* move simple auth users to master role
* make a kubeadm-specific env file for kubelet
* add non-ha CI job

* change ci boolean vars to json format

* fixup

* Update create-gce.yml

* Update create-gce.yml

* Update create-gce.yml

  * using separated vault roles for generate certs with different `O` (Organization) subject field;
  * configure vault roles for issuing certificates with different `CN` (Common name) subject field;
  * set `CN` and `O` to `kubernetes` and `etcd` certificates;
  * vault/defaults vars definition was simplified;
  * vault dirs variables defined in kubernetes-defaults foles for using
  shared tasks in etcd and kubernetes/secrets roles;
  * upgrade vault to 0.8.1;
  * generate random vault user password for each role by default;
  * fix `serial` file name for vault certs;
  * move vault auth request to issue_cert tasks;
  * enable `RBAC` in vault CI;

* Added update CA trust step for etcd and kube/secrets roles

* Added load_balancer_domain_name to certificate alt names if defined. Reset CA's in RedHat os.

* Rename kube-cluster-ca.crt to vault-ca.crt, we need separated CA`s for vault, etcd and kube.

* Vault role refactoring, remove optional cert vault auth because not not used and worked. Create separate CA`s fro vault and etcd.

* Fixed different certificates set for vault cert_managment

* Update doc/vault.md

* Fixed condition create vault CA, wrong group

* Fixed missing etcd_cert_path mount for rkt deployment type. Distribute vault roles for all vault hosts

* Removed wrong when condition in create etcd role vault tasks.

* Adding yaml linter to ci check

* Minor linting fixes from yamllint

* Changing CI to install python pkgs from requirements.txt

- adding in a secondary requirements.txt for tests
- moving yamllint to tests requirements

* Added custom ips to etcd vault distributed certificates

* Added custom ips to kube-master vault distributed certificates

* Added comment about issue_cert_copy_ca var in vault/issue_cert role file

* Generate kube-proxy, controller-manager and scheduler certificates by vault

* Revert "Disable vault from CI (#1546)"

This reverts commit 781f31d2.

* Fixed upgrade cluster with vault cert manager

* Remove vault dir in reset playbook

This does not address per-node certs and scheduler/proxy/controller-manager
component certs which are now required. This should be handled in a
follow-up patch.

without this etcd ca certs dont exist on worker nodes causing calico to fail

Make etcd_backup_prefix configurable. Ensures that backups can be stored on a different location other than ${HOST}/var/backups, say an EBS volume on AWS.

In the etcd container, the etcd data directory is always /var/lib/etcd. Reverting to this value, since `etcd_data_dir` on the host maps to `/var/lib/etcd` in the container.

Folded style in multiline 'when' condition causes error with
unexpected ident. Changing it to literal style should fix
the issue.

Closes #1190