Fixes #1012

Fix misleading HA docs

use ansible sysctl module for config ip forwarding

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

Kubernetes Reliability Improvements

Allow kubelet to load kernel modules

Enable weave upgrade from previous versions

removed explicit role for efk in cluster.yml

- Exclude kubelet CPU/RAM (kube-reserved) from cgroup. It decreases a
  chance of overcommitment
- Add a possibility to modify Kubelet node-status-update-frequency
- Add a posibility to configure node-monitor-grace-period,
  node-monitor-period, pod-eviction-timeout for Kubernetes controller
  manager
- Add Kubernetes Relaibility Documentation with recomendations for
  various scenarios.

Signed-off-by: Sergii Golovatiuk <sgolovatiuk@mirantis.com>

Raise readiness probe initial time to 60 (was 30)

fix kube_apiserver_ip/kube_apiserver_port description

Fix upgrade for all daemonset type resources

Update code and docs for that assumption.

kubelet lost the ability to load kernel modules.  This
puts that back by adding the lib/modules mount to kubelet.

The new variable kubelet_load_modules can be set to true
to enable this item.  It is OFF by default.

Lower weave RAM settings.

Adding vault role

enable proxy support on docker repository

Also add the system nameservers to upstream servers in dnsmasq

fix typo: "explicetely"

- Since Weave 1.8.x was rewritten in Golang we may decrease RAM settings
  to continue using g1-small for CI

Daemonsets cannot be simply upgraded through a single API call,
regardless of any kubectl documentation. The resource must be
purged and then recreated in order to make any changes.

Also make no-resolv unconditional again. Otherwise, we may end up in
a resolver loop. The resolver loop was the cause for the piling up
parallel queries.

Change docker save compress level to 1

Fix check for node-NODEID certs existence

Adding EFK logging stack

Host mount /dev for kubelet

Faster gzip improves CI deploy times by at least 2 mins.

Fixes #982

Re-tune ETCD performance params

Update playbooks to support new netchecker

Fixes upgrade from pre-individual node cert envs.