Install latest Virtualbox (version 6.1.10r138449)
Install latest vagrant (Version 2.2.9 at the time)
Install Ansible (ansible 2.9.10)

Follow steps 1), 2), 3) for quick setup

Vagrantfile is modified such that the memory size is 2048, cpus is 2 and docker is installed by shell commands and swap is turned off.

Steps to set-up
1) vagrant up
    - vagrant up spawns 2 VM's k8s-head and k8s-node-1 and provisioning done by setup.sh
    This is what happens via setup.sh in virtual machine (vagrant up will do this for you)
	- yum update
	- Docker installation:
		# (Install Docker CE)
		## Set up the repository
		### Install required packages
		yum install -y yum-utils device-mapper-persistent-data lvm2

		## Add the Docker repository
		yum-config-manager --add-repo \
		  https://download.docker.com/linux/centos/docker-ce.repo


		# Install Docker CE, version 19.03 is the recommended one via official kubeadm docs but 1.13.1, 17.03, 17.06, 17.09, 18.06 and 18.09 are known to work as well
		yum update -y && yum install -y \
		  containerd.io-1.2.13 \
		  docker-ce-19.03.11 \
		  docker-ce-cli-19.03.11

		## Create /etc/docker
		mkdir /etc/docker

		# Set up the Docker daemon
		cat > /etc/docker/daemon.json <<EOF
		{
		  "exec-opts": ["native.cgroupdriver=systemd"],
		  "log-driver": "json-file",
		  "log-opts": {
		    "max-size": "100m"
		  },
		  "storage-driver": "overlay2",
		  "storage-opts": [
		    "overlay2.override_kernel_check=true"
		  ]
		}
		EOF

		mkdir -p /etc/systemd/system/docker.service.d

		# Restart Docker
		systemctl daemon-reload
		systemctl restart docker

		# If you want the docker service to start on boot, run the following command:
		sudo systemctl enable docker

############## Vagrant up is completed, time to install SSH keys #############
we need to install ssh keys for our ansible scripts to work smoothly

2) ansible-playbook install_keys.yml -i inventory -u vagrant

    - we need to generate a pair of rsa/ed_25519 SSH keys and the ansible script install_keys.yml does it for us
        generate a random key/pair via script
        The ssh keys in the ssh_keys folder are to be setup on the vagrant machines (this could have been done from vagrant itself but the target
        of such scripts is to be tried on nodes already not having ssh keys).
        ssh add private key so that it doesnt ask for confirmation
        Also if there are problems of offending key make sure to check if your ~/.ssh/known_hosts you might need to clear any previoud entries
        you might have for k8s-head and k8s-node-1

3) ansible-playbook cluster-setup.yml -i inventory -u vagrant
	- installation of these packages on your machines: kubeadm, kubelet, kubectl
	- following commands (applies for CentOS, RHEL or Fedora)(https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/)
		cat <<EOF > /etc/yum.repos.d/kubernetes.repo
		[kubernetes]
		name=Kubernetes
		baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-\$basearch
		enabled=1
		gpgcheck=1
		repo_gpgcheck=1
		gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
		exclude=kubelet kubeadm kubectl
		EOF

		# Set SELinux in permissive mode (effectively disabling it)
		setenforce 0
		sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

		yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes

		systemctl enable --now kubelet

	- When using Docker, kubeadm will automatically detect the cgroup driver for the kubelet and set it in the /var/lib/kubelet/config.yaml file during runtime, so if you are using any other CRI check online docs.
	- Restarting the kubelet is required:
		systemctl daemon-reload
		systemctl restart kubelet

	- vagrant up will spawn two virtual machines
		- k8s-head supposed to be the master of the cluster with ip 192.168.205.10
		- k8s-node-1 supposed to be the worker of the cluster with ip 192.168.205.11

    Following stuff on master node
        - set hostname( can be moved to vagrant provision)
            [root@k8s-head vagrant]# HOST_NAME=$(hostname -s)

        - set IP address variable at k8s-head (this can be moved to vagrant provision)
            # IP_ADDR=192.168.205.10

        - kubeadm init with the following instructions
            [root@k8s-head vagrant]# kubeadm init --apiserver-advertise-address=$IP_ADDR --apiserver-cert-extra-sans=$IP_ADDR --node-name $HOST_NAME --pod-network-cidr=192.168.0.0/16

        - To start using your cluster, you need to run the following 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

    Following stuff on Future worker nodes
        - The next step is going to be to deploy a cluster so before that we should add the node 'k8s-node-1' to this cluster ( the command to add new nodes will be available when the cluster creation at master completes make sure to copy it from there)
            [root@k8s-node-1 vagrant]# kubeadm join 192.168.205.10:6443 --token yuc3ou.dyoai0yris8wszn9 \
            >     --discovery-token-ca-cert-hash sha256:78255514d13c5bf7f1bb3f8a3511fb1574e57c37fba984d7788a1d758c87446a

            OUTPUT

            W0627 13:03:32.561915   13838 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set.
            [preflight] Running pre-flight checks
            [preflight] Reading configuration from the cluster...
            [preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
            [kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.18" ConfigMap in the kube-system namespace
            [kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
            [kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
            [kubelet-start] Starting the kubelet
            [kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

            This node has joined the cluster:
            * Certificate signing request was sent to apiserver and a response was received.
            * The Kubelet was informed of the new secure connection details.

            Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

	- TODO Now on the master we deploy the calico networking pod config
		kubectl apply -f https://docs.projectcalico.org/v3.14/manifests/calico.yaml


######### After adding one more node and deploying calico pod network #########
	-	[vagrant@k8s-head ~]$ kubectl get pods --all-namespaces -o wide
		NAMESPACE     NAME                                       READY   STATUS    RESTARTS   AGE     IP                NODE         NOMINATED NODE   READINESS GATES
		kube-system   calico-kube-controllers-76d4774d89-5qqz2   0/1     Running   0          3m55s   192.168.193.193   k8s-head     <none>           <none>
		kube-system   calico-node-26v4w                          1/1     Running   0          3m56s   10.0.2.15         k8s-head     <none>           <none>
		kube-system   calico-node-bdf9k                          1/1     Running   0          3m56s   10.0.2.15         k8s-node-1   <none>           <none>
		kube-system   coredns-66bff467f8-l298d                   1/1     Running   0          19m     192.168.193.194   k8s-head     <none>           <none>
		kube-system   coredns-66bff467f8-rvspb                   0/1     Running   0          19m     192.168.109.65    k8s-node-1   <none>           <none>
		kube-system   etcd-k8s-head                              1/1     Running   0          20m     10.0.2.15         k8s-head     <none>           <none>
		kube-system   kube-apiserver-k8s-head                    1/1     Running   0          20m     10.0.2.15         k8s-head     <none>           <none>
		kube-system   kube-controller-manager-k8s-head           1/1     Running   2          20m     10.0.2.15         k8s-head     <none>           <none>
		kube-system   kube-proxy-59bld                           1/1     Running   0          15m     10.0.2.15         k8s-node-1   <none>           <none>
		kube-system   kube-proxy-mtl6r                           1/1     Running   0          19m     10.0.2.15         k8s-head     <none>           <none>
		kube-system   kube-scheduler-k8s-head                    1/1     Running   2          20m     10.0.2.15         k8s-head     <none>           <none>
		[vagrant@k8s-head ~]$ kubectl get nodes
		NAME         STATUS   ROLES    AGE   VERSION
		k8s-head     Ready    master   20m   v1.18.5
		k8s-node-1   Ready    <none>   15m   v1.18.5
		[vagrant@k8s-head ~]$