* Set host IP for kubelet always

Use ansible default IP if ip var is not set.

* Update main.yml

* update helm to v2.7.0

* Update main.yml

* Change deprecated vagrant ansible flag 'sudo' to 'become'

* Emphasize, that the name of the pip_pyton_modules is only considered in coreos

* Remove useless unused variable

* Fix warning when jinja2 template-delimiters used in when statement

There is no need for jinja2 template-delimiters like {{ }} or {% %}
any more. They can just be omitted as described in https://github.com/ansible/ansible/issues/22397

* Fix broken link in getting-started guide

* Change deprecated vagrant ansible flag 'sudo' to 'become'

* Workaround ansible bug where access var via dict doesn't get real value

When accessing a variable via it's name "{{ foo }}" its value is
retrieved. But when the variable value is retrieved via the vars-dict
"{{ vars['foo'] }}" this doesn't resolve the expression of the variable
any more due to a bug. So e.g. a expression foo="{{ 1 == 1 }}" isn't
longer resolved but just returned as string "1 == 1".

* Make file yamllint complient

Some time ago I think the hardcoded `/var/lib/docker` was required, but kubelet running in a container has been aware of the Docker path since at least as far back as k8s 1.6.

Without this change, you see a large number of errors in the kubelet logs if you installed with a non-default `docker_daemon_graph`

This allows overriding of apt repo endpoints when internet sources are not accessible. Additionally, switch to using the dockerproject.org gpg key url for apt instead of keyservers.net

All nodes get converted to lowercase, so certs should set
CN with lowercase as well.

Add reload yes to reload sysctl if the value of net.ipv4.ip_forward changes.

- name: Enable ip forwarding
  sysctl:
    sysctl_file: "{{sysctl_file_path}}"
    name: net.ipv4.ip_forward
    value: 1
    state: present
    reload: yes
  tags:
    - bootstrap-os

It is now enabled by default in 1.8 with the api changed
to networking.k8s.io/v1 instead of extensions/v1beta1.

This should be done after kubeconfig is set for admin and
before network plugins are up.

* Fix broken CI jobs

Adjust image and image_family scenarios for debian.
Checkout CI file for upgrades

* add debugging to file download

* Fix download for alternate playbooks

* Update ansible ssh args to force ssh user

* Update sync_container.yml

Also disable oom killer on etcd

This is to work around #1856 which can occur when kubelet
hostname and resolvable hostname (or cloud instance name)
do not match.

Signed-off-by: Haiwei Liu <carllhw@gmail.com>