CKA-1.2 Basic Setup (3 Node k8s cluster)

2 Jun 2023:

Setup:

• 3 node cluster with 1 control node.
• using vagrant and bash

requirements:

• ubuntu 20.04 focal vagrant box
• vagrant 2.3.4
• virtualbox 6.1

Steps overview for the basic setup:-

ensure that swap is disabled on all the nodes before starting the setup.

sudo swapoff -a

ensure following packages are installed in your system :-

packages :- apt-transport-https curl

sudo apt-get install -y apt-transport-https curl

Execute the following steps on all the nodes :-

1. setup the hostname across all the nodes, ensure that the appropriate mappings are present for all the nodes in /etc/hostname (use private ip)

2. Install containerd on all the nodes.

   • ensure that certain kernel modules are loaded before installation of other components:-

     • overlay
     • br_netfilter

     cat << EOF | sudo tee /etc/modules-load.d/containerd.conf
     overlay
     br_netfilter
     EOF

     load them using modprobe command, as follows :-

     sudo modprobe overlay sudo modprobe br_netfilter

   • ensure that the networking configs (system level) are present.

     cat << EOF | sudo tee /etc/sysctl.d/99-k8s-cri.conf net.bridge.bridge-nf-call-iptables = 1 net.ipv4.ip_forward = 1 net.bridge.bridge-nf-call-ip6tables = 1 EOF

     loaded at restart, optionally if need to reload immediately execute the following:-

     sysctl --system

3. install and configure containerd and docker

   for pkg in docker.io docker-doc docker-compose podman-docker containerd runc; do sudo apt-get remove $pkg; done

   sudo apt-get update

   sudo apt-get install ca-certificates curl gnupg -y

   sudo install -m 0755 -d /etc/apt/keyrings

   curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg sudo chmod a+r /etc/apt/keyrings/docker.gpg

   echo
   "deb [arch="$(dpkg --print-architecture)" signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu
   "$(. /etc/os-release && echo "$VERSION_CODENAME")" stable" |
   sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

   sudo apt-get update

   sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin -y

4. setup k8s package repository

   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

5. install k8s packages

   We install following 3 packages:- * kubelet * kubeadm * kubectl

   sudo apt-get install -y kubelet=1.24.0-00 kubeadm=1.24.0-00 kubectl=1.24.0-00

   You can edit the version as per your requirement. I used 1.24.0-00

6. hold the packages (mark them) from auto upgrade.

   sudo apt-mark hold kubelet kubeadm kubectl