Install Kubernetes Cluster On Ubuntu

Install Kubernetes Cluster using kubeadm

Follow this documentation to set up a Kubernetes cluster on Ubuntu 20.04 LTS.

This documentation guides you in setting up a cluster with one master node and one worker node.

Assumptions

|Role|FQDN|IP|OS|RAM|CPU| |—-|—-|—-|—-|—-|—-| |Master|kmaster.example.com|192.168.3.105|Ubuntu 20.04|2G|2| |Worker|kworker1.example.com|1192.168.3.104|Ubuntu 20.04|1G|1| |Worker|kworker2.example.com|1192.168.3.106|Ubuntu 20.04|1G|1|

On both Kmaster and Kworker

Login as root user

sudo su -

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-focal 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 kubelet kubectl

In case you are using LXC containers for Kubernetes nodes

Hack required to provision K8s v1.15+ in LXC containers

{
  mknod /dev/kmsg c 1 11
  echo '#!/bin/sh -e' >> /etc/rc.local
  echo 'mknod /dev/kmsg c 1 11' >> /etc/rc.local
  chmod +x /etc/rc.local
}

On kmaster

Initialize Kubernetes Cluster

Update the below command with the ip address of kmaster

kubeadm config images pull --image-repository=registry.aliyuncs.com/google_containers

kubeadm init  --apiserver-advertise-address=192.168.3.105 \
--image-repository=registry.aliyuncs.com/google_containers  \
--pod-network-cidr=192.168.0.0/16 \
--ignore-preflight-errors=swap

# kubeadm init --apiserver-advertise-address=192.168.3.105 --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/v3.20/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 (On kmaster)

Get Nodes status

kubectl get nodes

Get component status

kubectl get cs

Have Fun!!