Add a k8s app for advanced e2e netcheck for DNS

* Add an option to deploy K8s app to test e2e network connectivity
  and cluster DNS resolve via Kubedns for nethost/simple pods
  (defaults to false).
* Parametrize existing k8s apps templates with kube_namespace and
  kube_config_dir instead of hardcode.
* For CoreOS, ensure nameservers from inventory to be put in the
  first place to allow hostnet pods connectivity via short names
  or FQDN and hostnet agents to pass as well, if netchecker
  deployed.

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

Tune dnsmasq/kubedns limits, replicas, logging

Decouple etcd/k8s-cluster roles in ec2 terraform

Update default calico/ctl image tag

* Add dns_replicas, dns_memory/cpu_limit/requests vars for
dns related apps.
* When kube_log_level=4, log dnsmasq queries as well.
* Add log level control for skydns (part of kubedns app).
* Add limits/requests vars for dnsmasq (part of kubedns app) and
  dnsmasq daemon set.
* Drop string defaults for kube_log_level as it is int and
  is defined in the global vars as well.
* Add docs

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

We no longer need to use v0.22.0 for calicoctl since Kargo has
support for new calicoctl CLI format.

Also fixing condition logic for calico pool task.

Fix download dnsmasq image dependency on docker

Fix Calico jinja template (systemd)

When download_run_once with download_localhost is used, docker is
expected to be running on the delegate localhost. That may be not
the case for a non localhost delegate, which is the kube-master
otherwise. Then the dnsmasq role, had it been invoked early before
deployment starts, would fail because of the missing docker dependency.

* Fix that dependency on docker and do not pre download dnsmasq image
  for the dnsmasq role, if download_localhost is disabled.
* Remove become: false for docker CLI invocation because that's not
  the common pattern to allow users access docker CLI w/o sudo.
* Fix opt bin path hack for localhost delegate to ignore errors when
  it fails with "sudo password required" otherwise.
* Describe download_run_once with download_localhost use case in docs
  as well.

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

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>

Currently, the terraform script in contrib
adds etcd role as a child of k8s-cluster in
its generated inventory file.

This is problematic when the etcd role is
deployed on separate nodes from the k8s master
and nodes. In this case, this leads to failures
of the k8s node since the PKI certs required for
that role have not been propogated.

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.