Setup a multinode cluster of kubernetes on Ubuntu 16.04

kubeadm-Ubuntu-16.04.md

Install Kubernetes Cluster using kubeadm

I used VirtualBox image of Ubuntu 16.04.6 Xenial from OSBoxes

Assumptions

Role	FQDN	IP	OS	RAM	CPU
Master	kmaster.example.com	192.168.56.2	Ubuntu 16.04.6	2G	2
Worker	kworker.example.com	192.168.56.3	Ubuntu 16.04.6	1G	1
Worker	kworker.example.com	192.168.56.4	Ubuntu 16.04.6	1G	1

You can use virualbox Host only network to set these IP. Then update the followings:

/etc/hostname
/etc/hosts
/etc/network/interfaces #to give static IP from new Hostonly network 

On both Kmaster and Kworker

Perform all the commands as root user unless otherwise specified

Disable Firewall

ufw disable

Disable swap

swapoff -a; sed -i '/swap/d' /etc/fstab

Update sysctl settings for Kubernetes networking

cat >>/etc/sysctl.d/kubernetes.conf<<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

Install docker engine

{
  apt install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common
  curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
  add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
  apt update
  apt install -y docker-ce=5:19.03.10~3-0~ubuntu-xenial containerd.io
}

Kubernetes Setup

Add Apt repository

{
  curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
  echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" > /etc/apt/sources.list.d/kubernetes.list
}

Install Kubernetes components

apt update && apt install -y kubeadm=1.18.5-00 kubelet=1.18.5-00 kubectl=1.18.5-00

On kmaster

Initialize Kubernetes Cluster

Update the below command with the ip address of kmaster

kubeadm init --apiserver-advertise-address=172.16.16.100 --pod-network-cidr=192.168.0.0/16  --ignore-preflight-errors=all

Deploy Calico network

kubectl --kubeconfig=/etc/kubernetes/admin.conf create -f https://docs.projectcalico.org/v3.14/manifests/calico.yaml

Cluster join command

kubeadm token create --print-join-command

To be able to run kubectl commands as non-root user

If you want to be able to run kubectl commands as non-root user, then as a non-root user perform these

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

On Kworker

Join the cluster

Use the output from kubeadm token create command in previous step from the master server and run here.

Verifying the cluster

Get Nodes status

kubectl get nodes

Get component status

kubectl get cs