5. Kubeadm Installation Guide

This guide outlines the steps needed to set up a Kubernetes cluster using kubeadm.

Prerequisites

• Ubuntu OS (Xenial or later)

• sudo privileges

• Internet access

• t2.medium instance type or higher

• Minimum 20GB Volume

AWS Setup

1. Ensure that all instances are in the same Security Group.

2. Expose port 6443 in the Security Group to allow worker nodes to join the cluster.

3. Expose port 22 in the Security Group to allows SSH access to manage the instance..

To do above setup, follow below provided steps

Step 1: Identify or Create a Security Group

1. Log in to the AWS Management Console:

   • Go to the EC2 Dashboard.

2. Locate Security Groups:

   • In the left menu under Network & Security, click on Security Groups.

3. Create a New Security Group:

   • Click on Create Security Group

     

   • Provide the following details:

     • Name: (e.g., Kubernetes-Cluster-SG)

     • Description: A brief description for the security group (mandatory)

     • VPC: Select the appropriate VPC for your instances (default is acceptable)

       

4. Add Rules to the Security Group:

   • Allow SSH Traffic (Port 22):

     • Type: SSH

     • Port Range: 22

     • Source: 0.0.0.0/0 (Anywhere) or your specific IP

   • Allow Kubernetes API Traffic (Port 6443):

     • Type: Custom TCP

     • Port Range: 6443

     • Source: 0.0.0.0/0 (Anywhere) or specific IP ranges

       

5. Save the Rules:

   • Click on Create Security Group to save the settings

     

Step 2: Select the Security Group While Creating Instances

• When launching EC2 instances:

  • Under Configure Security Group, select the existing security group (Kubernetes-Cluster-SG)

Note: Security group settings can be updated later as needed.

Execute on Both "Master" & "Worker" Nodes

1. Disable Swap: Required for Kubernetes to function correctly.

    sudo swapoff -a
   

2. Load Necessary Kernel Modules: Required for Kubernetes networking.

    cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
    overlay
    br_netfilter
    EOF
   
    sudo modprobe overlay
    sudo modprobe br_netfilter
   

3. Set Sysctl Parameters: Helps with networking.

    cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
    net.bridge.bridge-nf-call-iptables  = 1
    net.bridge.bridge-nf-call-ip6tables = 1
    net.ipv4.ip_forward                 = 1
    EOF
   
    sudo sysctl --system
    lsmod | grep br_netfilter
    lsmod | grep overlay
   

4. Install Containerd:

    sudo apt-get update
    sudo apt-get install -y ca-certificates curl
    sudo install -m 0755 -d /etc/apt/keyrings
    sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
    sudo chmod a+r /etc/apt/keyrings/docker.asc
   
    echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] 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 -y containerd.io
   
    containerd config default | sed -e 's/SystemdCgroup = false/SystemdCgroup = true/' -e 's/sandbox_image = "registry.k8s.io\/pause:3.6"/sandbox_image = "registry.k8s.io\/pause:3.9"/' | sudo tee /etc/containerd/config.toml
   
    sudo systemctl restart containerd
    sudo systemctl status containerd
   

5. Install Kubernetes Components:

    sudo apt-get update
    sudo apt-get install -y apt-transport-https ca-certificates curl gpg
   
    curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.29/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
   
    echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.29/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list
   
    sudo apt-get update
    sudo apt-get install -y kubelet kubeadm kubectl
    sudo apt-mark hold kubelet kubeadm kubectl
   

Execute ONLY on the "Master" Node

1. Initialize the Cluster:

    sudo kubeadm init
   

   

2. Set Up Local kubeconfig:

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

   

3. Install a Network Plugin (Calico):

    kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.0/manifests/calico.yaml
   

   

1. Generate Join Command:

    kubeadm token create --print-join-command
   

Copy this generated token for next command

.

Execute on ALL of your Worker Nodes

1. Perform pre-flight checks:

    sudo kubeadm reset pre-flight checks
   

2. Paste the join command you got from the master node and append --v=5 at the end:

    sudo kubeadm join <private-ip-of-control-plane>:6443 --token <token> --discovery-token-ca-cert-hash sha256:<hash> --cri-socket 
    "unix:///run/containerd/containerd.sock" --v=5
   

   Note: When pasting the join command from the master node:

   1. Add sudo at the beginning of the command

   2. Add --v=5 at the end

   Example format:

   sudo <paste-join-command-here> --v=5
   

   

Verify Cluster Connection

On Master Node:

kubectl get nodes