[Doc] --fail-swap-on=False is necessary for KUBELET_EXTRA_ARGS

[Yushiro FURUKAWA]

In the latest deployment-guide(https://docs.openstack.org/kolla-kubernetes/latest/deployment-guide.html), kubelet doesn't start because following definition is missing in /etc/systemd/system/kubelet.service.d/10-kubeadm.conf:

  Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false"

[Environment]
  os: Ubuntu16.04.3 LTS All-in-One node

[Without definition(Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false")]
$ sudo kubeadm init --pod-network-cidr=10.1.0.0/16 --service-cidr=10.3.3.0/24
[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[init] Using Kubernetes version: v1.8.5
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks
[preflight] Some fatal errors occurred:
    running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`

[With definition(Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false")]
$ sudo kubeadm init --pod-network-cidr=10.1.0.0/16 --service-cidr=10.3.3.0/24
[kubeadm] WARNING: kubeadm is in beta, please do not use it for production clusters.
[init] Using Kubernetes version: v1.8.5
[init] Using Authorization modes: [Node RBAC]
[preflight] Running pre-flight checks
[preflight] Some fatal errors occurred:
    running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can skip pre-flight checks with `--skip-preflight-checks`

[With definition(Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false") with --skip-preflight-checks]
$ sudo kubeadm init --pod-network-cidr=10.1.0.0/16 --service-cidr=10.3.3.0/24 --skip-preflight-checks
..(snip)..
Your Kubernetes master has initialized successfully!
To start using your cluster, you need to run (as a regular user):
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
http://kubernetes.io/docs/admin/addons/

As a result, in order to run kubeadm init, following parameters are missing:

  1. Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false" at /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

  2. --skip-preflight-checks option for kubeadm init

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/527416

[OpenStack Infra (hudson-openstack)]

Change abandoned by Yushiro FURUKAWA (<email address hidden>) on branch: master
Review: https://review.openstack.org/527416
Reason: move to https://review.openstack.org/#/c/524125/