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Korakrit Chariyasathian
Korakrit Chariyasathian

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Installing Kubernetes and Worker Node Setup on Ubuntu 24.04

#devops #kubernetes #ubuntu #tutorial

Kubernetes Setup on Ubuntu 24.04 (Kubernetes v1.33)

1. Prepare the Ubuntu VM

Update system packages:

sudo apt update && sudo apt upgrade -y
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Disable swap (required by Kubernetes):

sudo swapoff -a
sudo sed -i '/ swap / s/^/#/' /etc/fstab
sudo sed -i '/swap.img/ s/^/#/' /etc/fstab
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2. Enable Kernel Modules and Sysctl Settings

Load required kernel modules:

sudo modprobe overlay
sudo modprobe br_netfilter
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Ensure they load on boot:

cat <<EOF | sudo tee /etc/modules-load.d/kubernetes.conf
overlay
br_netfilter
EOF
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Set required sysctl parameters:

sudo tee /etc/sysctl.d/kubernetes.conf <<EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOF
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Apply sysctl changes:

sudo sysctl --system
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3. Install and Configure Containerd (Container Runtime)

Kubernetes v1.33 requires CRI v1. Docker (dockershim) is not supported.

Install containerd:

sudo apt install -y containerd
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Generate the default containerd configuration:

sudo mkdir -p /etc/containerd
sudo containerd config default | sudo tee /etc/containerd/config.toml > /dev/null
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Enable systemd cgroup:

sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml
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Restart and enable containerd:

sudo systemctl daemon-reload
sudo systemctl enable --now containerd
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Note: The CRI plugin is enabled by default in a standard containerd package config. You generally do not need to manually add a CRI block. If you choose to verify, ensure the CRI plugin section is present and not disabled. The pause image you referenced is reasonable.
Ensure the CRI plugin is enabled:

[plugins."io.containerd.grpc.v1.cri"]
  sandbox_image = "registry.k8s.io/pause:3.10"
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Restart and enable containerd:

sudo systemctl restart containerd
sudo systemctl enable containerd
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4. Add the Kubernetes APT Repository (v1.33) 

sudo apt install -y apt-transport-https ca-certificates curl gpg
sudo mkdir -p /etc/apt/keyrings
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curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.33/deb/Release.key | \
sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
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echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] \
https://pkgs.k8s.io/core:/stable:/v1.33/deb/ /" | \
sudo tee /etc/apt/sources.list.d/kubernetes.list
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sudo apt update
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5. Install Kubernetes Tools 

sudo apt install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl
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(Optional but common) Ensure kubelet is enabled:

sudo systemctl enable --now kubelet
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6. Install Helm 

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash
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Verify Helm and add repositories:

helm version
helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm repo update
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7. Initialize the Kubernetes Control Plane 

sudo kubeadm init --pod-network-cidr=10.0.0.0/16
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8. Set Up kubeconfig 

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

kubectl get nodes
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  • The node will show NotReady until a CNI plugin is installed.
  • Output: is-kube shows as NotReady (because Pod Network is not yet installed)

Install Cilium CNI

Install cilium-cli

Download the Cilium CLI:

curl -L --remote-name https://github.com/cilium/cilium-cli/releases/latest/download/cilium-linux-amd64.tar.gz
sudo tar xzvf cilium-linux-amd64.tar.gz -C /usr/local/bin
rm cilium-linux-amd64.tar.gz
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Install Cilium

Install Cilium into the cluster:

cilium install
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Verify Cluster Status 

kubectl get nodes
cilium status
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Worker Node Setup

1. Prepare the Ubuntu VM

Update system packages:

sudo apt update && sudo apt upgrade -y
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sudo swapoff -a
sudo sed -i '/ swap / s/^/#/' /etc/fstab
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2. Setup kernel modules and sysctl 

sudo modprobe overlay
sudo modprobe br_netfilter

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

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

sudo sysctl --system
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3. Install and configure containerd 

sudo apt install -y containerd

sudo mkdir -p /etc/containerd
sudo containerd config default | sudo tee /etc/containerd/config.toml > /dev/null

sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml

sudo systemctl daemon-reload
sudo systemctl enable --now containerd
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4. Add Kubernetes apt repo (v1.33) and install kubelet/kubeadm 

sudo apt install -y apt-transport-https ca-certificates curl gpg
sudo mkdir -p /etc/apt/keyrings

curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.33/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:/v1.33/deb/ /" | \
sudo tee /etc/apt/sources.list.d/kubernetes.list > /dev/null

sudo apt update
sudo apt install -y kubelet kubeadm
sudo apt-mark hold kubelet kubeadm

sudo systemctl enable --now kubelet
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Join the worker to the cluster

1. Create Kubernetes Cluster's Token

Run this on the control-plane node:

kubeadm token create --print-join-command
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  • It prints something like:

sudo kubeadm join <CONTROL_PLANE_IP>:6443 --token <TOKEN> --discovery-token-ca-cert-hash sha256:<HASH>

2. Run that join command on the worker

Paste and run it on the worker node (with sudo).

sudo kubeadm join <CONTROL_PLANE_IP>:6443 --token <TOKEN> --discovery-token-ca-cert-hash sha256:<HASH>
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3. Verify from the Control Plane 

kubectl get nodes -o wide
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