1. Install 4 Ubuntu machines using Virtual Box. One machine will be Kubernetes master node and 3 others will be Kubernetes worker nodes. On each of the machines it will be installed Ubuntu 20.04 OS. 2. Ubuntu Machines:	k8s-m	k8s-w1	k8s-w2	k8s-w3 Each machine has Static IP On each machine /etc/hosts	192.168.1.103	k8s-m	192.168.1.x	k8s-w1	192.168.1.y	k8s-w2	192.168.1.z	k8s-w3 3. On each machine install curl: sudo apt install curl 4. On each machine install docker: sudo apt-get remove docker docker-engine docker.io sudo apt install docker.io sudo systemctl start docker sudo systemctl enable docker dmi@k8s-m:~$ sudo systemctl status docker ● docker.service - Docker Application Container Engine Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled) Active: active (running) since Sun 2020-06-21 01:47:40 IDT; 2h 2min ago TriggeredBy: ● docker.socket Docs: https://docs.docker.com Main PID: 720 (dockerd) Tasks: 18 Memory: 71.4M CGroup: /system.slice/docker.service └─720 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock docker --version 5. Add the Kubernetes signing key on all on each machines: curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add 6. Add Xenial Kubernetes Repository on all the machines: sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main" 7. Install Kubeadm on each machines: sudo apt install kubeadm kubeadm version 8. Disable swap memory on all the machines: sudo swapoff -a 9. Set corresponding hostnames (we have 1 master node and 3 worker nodes): sudo hostnamectl set-hostname k8s-m sudo hostnamectl set-hostname k8s-w1 sudo hostnamectl set-hostname k8s-w2 sudo hostnamectl set-hostname k8s-w3 10. Some additional settings: cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf net.bridge.bridge-nf-call-ip6tables = 1 net.bridge.bridge-nf-call-iptables = 1 EOF sudo sysctl --system sudo apt-get update && sudo apt-get install -y apt-transport-https curl curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list deb https://apt.kubernetes.io/ kubernetes-xenial main EOF sudo apt-get update sudo apt-get install -y kubelet kubeadm kubectl sudo apt-mark hold kubelet kubeadm kubectl 11. Initialize Kubernetes on the master node as root: kubeadm init --apiserver-advertise-address=<ip-address-of-k8s-m> --pod-network-cidr=192.168.0.0/16 Output: ... Your Kubernetes control-plane has initialized successfully! 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) $HOME/.kube/config You should now deploy a pod network to the cluster. Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at: https://kubernetes.io/docs/concepts/cluster-administration/addons/ Then you can join any number of worker nodes by running the following on each as root: kubeadm join 192.168.1.103:6443 --token e1f19s.h04glij8wo1wjoym --discovery-token-ca-cert-hash sha256:efec132fe702df832f24bfb09f5aa299ef871677ecfbd16c18c333188f376e0f 12. Check the status of the master node by running: kubectl get nodes dmi@k8s-m:~$ kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-m NotReady master 13m v1.18.4 dmi@k8s-m:~$ 13. Deploy a Pod Network through the master node A pod network is a medium of communication between the nodes of a network. We are deploying a Flannel pod network on our cluster through the following command. We run it on master node: kubectl apply -f https://github.com/coreos/flannel/blob/master/Documentation/kube-flannel.yml dmi@k8s-m:~$ kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml podsecuritypolicy.policy/psp.flannel.unprivileged created clusterrole.rbac.authorization.k8s.io/flannel created clusterrolebinding.rbac.authorization.k8s.io/flannel created serviceaccount/flannel created configmap/kube-flannel-cfg created daemonset.apps/kube-flannel-ds-amd64 created daemonset.apps/kube-flannel-ds-arm64 created daemonset.apps/kube-flannel-ds-arm created daemonset.apps/kube-flannel-ds-ppc64le created daemonset.apps/kube-flannel-ds-s390x created dmi@k8s-m:~$ 14. Join Kubernetes worker nodes: Run kubeadm join kubeadm join 192.168.1.103:6443 --token e1f19s.h04glij8wo1wjoym --discovery-token-ca-cert-hash sha256:efec132fe702df832f24bfb09f5aa299ef871677ecfbd16c18c333188f376e0f from each worker node: root@k8s-w3:/home/dmi# kubeadm join 192.168.1.103:6443 --token e1f19s.h04glij8wo1wjoym --discovery-token-ca-cert-hash sha256:efec132fe702df832f24bfb09f5aa299ef871677ecfbd16c18c333188f376e0f W0621 03:48:50.270266 6988 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set. [preflight] Running pre-flight checks	[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/ [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. root@k8s-w3:/home/dmi# 15. Use the following commands in order to view the status: dmi@k8s-m:~$ kubectl get pods --all-namespaces NAMESPACE NAME READY STATUS RESTARTS AGE kube-system coredns-66bff467f8-g7sbv 1/1 Running 0 24m kube-system coredns-66bff467f8-q44rx 1/1 Running 0 24m kube-system etcd-k8s-m 1/1 Running 0 25m kube-system kube-apiserver-k8s-m 1/1 Running 0 25m kube-system kube-controller-manager-k8s-m 1/1 Running 0 25m kube-system kube-flannel-ds-amd64-lcm7b 1/1 Running 0 22m kube-system kube-flannel-ds-amd64-sn8l8 0/1 Evicted 0 5m42s kube-system kube-flannel-ds-amd64-zx4dn 1/1 Running 0 10m kube-system kube-flannel-ds-amd64-zzfxw 1/1 Running 2 9m58s kube-system kube-proxy-9jwxv 1/1 Running 0 10m kube-system kube-proxy-9nh4d 1/1 Running 0 16m kube-system kube-proxy-hrwsj 1/1 Running 0 9m58s kube-system kube-proxy-xqk94 1/1 Running 0 24m kube-system kube-scheduler-k8s-m 1/1 Running 0 25m dmi@k8s-m:~$ dmi@k8s-m:~$ kubectl get nodes NAME STATUS ROLES AGE VERSION k8s-m Ready master 26m v1.18.4 k8s-w1 Ready <none> 17m v1.18.4 k8s-w2 Ready <none> 11m v1.18.4 k8s-w3 Ready <none> 11m v1.18.4 dmi@k8s-m:~$