Ensure /etc/resolv.conf content for CoreOS

Use cloud-init config to replace /etc/resolv.conf with the
content for kubelet to properly configure hostnet pods.

Do not use systemd-resolved yet, see
https://coreos.com/os/docs/latest/configuring-dns.html


"Only nss-aware applications can take advantage of the
systemd-resolved cache. Notably, this means that statically
linked Go programs and programs running within Docker/rkt
will use /etc/resolv.conf only, and will not use the
systemd-resolve cache."

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Fix nginx container download for download_run_once mode

W/o this patch, the "Download containers" task may be skipped
when running on the delegate node due to wrong "when" confition.
Then it fails to upload nginx image to the nodes as well.

Fix download nginx dependency so it always can be pushed to
nodes when download_run_once is enabled.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Allow pre-downloaded images to be used effectively

Set defaults for ansible_ssh_user

When setting permission for containers download/upload dir we're
using `ansible_ssh_user`. But if playbook is executed without
user being explicitly set `ansible_ssh_user` may be undefined.
In such situations dir ownership will default to `ansible_user_id`

Closes: #644

According to http://kubernetes.io/docs/user-guide/images/

 :
By default, the kubelet will try to pull each image from the
specified registry. However, if the imagePullPolicy property
of the container is set to IfNotPresent or Never, then a local\
image is used (preferentially or exclusively, respectively).

Use IfNotPresent value to allow images prepared by the download
role dependencies to be effectively used by kubelet without pull
errors resulting apps to stay blocked in PullBackOff/Error state
even when there are images on the localhost exist.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Fix conditional when setting loadbalancer_apiserver_localhost

Add ability to define network backend for Calico.

Download images as dependencies of roles

Increase wait for pods post-install test

Pre download all required container images as roles' deps.
Drop unused flannel-server-helper images pre download.
Improve pods creation post-install test pre downloaded busybox.
Improve logs collection script with kubectl describe, fix sudo/etcd/weave
commands.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

The test deployment/rc/pods creation time
is near 2m on slow CI instances with 1 CPU/1.7G RAM.
Increase wait time to allow the post test fail less often.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Add missing liveness probe for apiserver static pod

Fix unreliable waiting for the apiserver to become ready.
Remove logfile mount to align with the rest of static pods
and because containers shall write logs to stdout only.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Fix download once

Ensure that etcd health checks always pass

Allow failures for coreos/weave

Add service-node-port-range parameter for kube-apiserver

in the etcd handler, the reload etcd action
was called after ansible waits for etcd to be
up, this means that the health checks which are
called immediately after fail (resulting in the etcd
role always failing and never finishing)

This patch changes the order to move the 'wait for etcd
up' resource after the 'reload etcd resource', ensuring that
the service is up before the health check is called.

Unless https://github.com/kubernetes-incubator/kargo/issues/613


fixed.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

* Add download_localhost for the download_run_once mode, which is
  use the ansible host (a travis node for CI case) to store and
  distribute containers across cluster nodes in inventory.
  Defaults to false.
* Rework download_run_once logic to fix idempotency of uploading
  containers.
* For Travis CI, enable docker images caching and run Travis
  workers with sudo enabled as a dependency
* For Travis CI, deploy with download_localhost and download_run_once
  enabled to shourten dev path drastically.
* Add compression for saved container images. Defaults to 'best'.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>
Co-authored-by: Aleksandr Didenko <adidenko@mirantis.com>

This patch introduce `calico_network_backend` global variable,
which allow to describe alternative network backend.
Default behavior is unchanged.

Add one more step (task) to containers download/upload sequence -
copy saved .tar containers to ansible host (delegate_to: localhost).

Then upload images to target nodes. It uses synchronize module so
if ansible host (localhost) is the same host as kube-master[0] then
new task causes no issues and the copy to localhost process is
basically skipped.

Update roadmap.md

Fix collect/upload logs for CoreOS

Fix failure if image package index is outdated

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

Fix inventory example

Moved the variable setting to the apt-get install part where it matters as requested in the review.

Fix sugested bootstrap options

Improve CI test matrix

Move CNI config and add MTU support for calico-cni

For Travis CI and GCE, add a naive generator script into a markdown table.
Add GCE/Travis CI matrix docs.
Add CoreOS test cases.
Rework existing cases w/o loosing of coverage.
Rework postinstall tests to support CoreOS as well.

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

- Move CNI configuration creation for Calico to appropriate
network_plugin role from kubernetes/node.
- Add support for MTU configuration in Calico.