Compose-Files/Backups/Miker/Bookstack/kubernetes.md

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Documentation Bookstack Notes

Kubernetes

☸️ Production-Ready Kubernetes Setup Guide (Ubuntu)

This guide walks you through setting up a Kubernetes cluster using kubeadm on Ubuntu Server (20.04, 22.04, or 24.04).

1. Prerequisites & Resource Allocation

Ensure all machines in your planned cluster meet the following baseline requirements:

• Operating System: Clean installation of Ubuntu Server on all nodes.
• Master Node: Minimum 2 vCPUs, 4GB RAM, and 50GB storage.
• Worker Nodes: Minimum 1 vCPU (2 recommended), 2GB RAM (4GB recommended).
• Network: Unique hostnames, MAC addresses, and product_uuids for every node. Fully static IP addresses are highly recommended.

2. Preparation (Execute on ALL Nodes)

Run these steps across every machine (Master and Workers) to prepare the operating system.

Step 2.1: System Update & Disable Swap

Kubernetes requires swap memory to be completely disabled to ensure kubelet resource scheduling works deterministically.

Bash

``` # Update local package lists and upgrade existing software sudo apt update && sudo apt upgrade -y

Disable swap immediately

sudo swapoff -a

Persist the change across reboots by commenting out the swap line in /etc/fstab

sudo sed -i '/ swap / s/^(.*)$/#\1/g' /etc/fstab

<div class="code-block ng-tns-c1605810258-279 ng-animate-disabled ng-trigger ng-trigger-codeBlockRevealAnimation" id="bkmrk--1"><div class="formatted-code-block-internal-container ng-tns-c1605810258-279"><div class="animated-opacity ng-tns-c1605810258-279"></div></div></div>### Step 2.2: Configure Kernel Modules and Networking

Load the necessary kernel modules for container isolation and networking, and configure required `sysctl` network parameters.

<div class="code-block ng-tns-c1605810258-280 ng-animate-disabled ng-trigger ng-trigger-codeBlockRevealAnimation" id="bkmrk-bash-1"><div class="formatted-code-block-internal-container ng-tns-c1605810258-280"><div class="animated-opacity ng-tns-c1605810258-280"><div class="code-block-decoration header-formatted gds-emphasized-body-m ng-tns-c1605810258-280 ng-star-inserted"><span class="ng-tns-c1605810258-280">Bash</span><div class="buttons ng-tns-c1605810258-280 ng-star-inserted"></div></div></div></div></div>```
# Configure modules to load automatically on boot
cat <<EOF | sudo tee /etc/modules-load.d/k8s.conf
overlay
br_netfilter
EOF

# Load the modules into the current kernel session
sudo modprobe overlay
sudo modprobe br_netfilter

# Enable IPv4 forwarding and iptables bridging rules
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

# Apply sysctl parameters immediately without a reboot
sudo sysctl --system

### Step 2.3: Install and Configure Containerd (CRI)

We will install containerd, generate its default configurations, and explicitly enable the SystemdCgroup driver so it aligns properly with Kubernetes' cgroup management.

Bash

``` # Install the containerd package sudo apt update && sudo apt install -y containerd

Generate default configuration directory and file

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

Configure containerd to use SystemdCgroup

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

Restart and enable containerd service

sudo systemctl restart containerd sudo systemctl enable containerd

<div class="code-block ng-tns-c1605810258-281 ng-animate-disabled ng-trigger ng-trigger-codeBlockRevealAnimation" id="bkmrk--7"><div class="formatted-code-block-internal-container ng-tns-c1605810258-281"><div class="animated-opacity ng-tns-c1605810258-281"></div></div></div>### Step 2.4: Install Kubernetes CLI/Server Tools (`pkgs.k8s.io`)

This pulls from the modernized community-hosted repositories. *(Note: Adjust `v1.30` in the path if you intend to pin your cluster to a specific minor edition).*

<div class="code-block ng-tns-c1605810258-282 ng-animate-disabled ng-trigger ng-trigger-codeBlockRevealAnimation" id="bkmrk-bash-3"><div class="formatted-code-block-internal-container ng-tns-c1605810258-282"><div class="animated-opacity ng-tns-c1605810258-282"><div class="code-block-decoration header-formatted gds-emphasized-body-m ng-tns-c1605810258-282 ng-star-inserted"><span class="ng-tns-c1605810258-282">Bash</span><div class="buttons ng-tns-c1605810258-282 ng-star-inserted"></div></div></div></div></div>```
# Download dependencies for secure repository signatures
sudo apt-get update && sudo apt-get install -y apt-transport-https ca-certificates curl gpg

# Download the public signing key for the modern Kubernetes package repository
sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.30/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg

# Add the correct apt repository reference string
echo 'deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://pkgs.k8s.io/core:/stable:/v1.30/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Update your lists and install the core binaries
sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl

# Prevent accidental background package upgrades from breaking cluster state
sudo apt-mark hold kubelet kubeadm kubectl

## 3. Control Plane Initialization (Execute on MASTER Node Only)

Step 3.1: Initialize via Kubeadm

Choose your Pod network CIDR block. If using Calico, the default block is 192.168.0.0/16. If using Flannel, the default block is 10.244.0.0/16.

Bash

``` # Initialize the master plane node (Using Calico default networking block) sudo kubeadm init --pod-network-cidr=192.168.0.0/16

<div class="code-block ng-tns-c1605810258-283 ng-animate-disabled ng-trigger ng-trigger-codeBlockRevealAnimation" id="bkmrk--13"><div class="formatted-code-block-internal-container ng-tns-c1605810258-283"><div class="animated-opacity ng-tns-c1605810258-283"></div></div></div>*(Once complete, look at the end of your terminal output. Copy and save the unique `kubeadm join` block generated—you will need it for your workers).*

### Step 3.2: Configure local `kubectl` access

To allow your non-root system user account to issue instructions to the API server:

<div class="code-block ng-tns-c1605810258-284 ng-animate-disabled ng-trigger ng-trigger-codeBlockRevealAnimation" id="bkmrk-bash-5"><div class="formatted-code-block-internal-container ng-tns-c1605810258-284"><div class="animated-opacity ng-tns-c1605810258-284"><div class="code-block-decoration header-formatted gds-emphasized-body-m ng-tns-c1605810258-284 ng-star-inserted"><span class="ng-tns-c1605810258-284">Bash</span><div class="buttons ng-tns-c1605810258-284 ng-star-inserted"></div></div></div></div></div>```
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

### Step 3.3: Deploy the Pod CNI (Calico Deployment)

Deploying a single clear network operator ensures network tracking stays clean.

Bash

``` # Install the Tigera Calico Operator kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.0/manifests/tigera-operator.yaml

Download the custom resource manifest definition

wget https://raw.githubusercontent.com/projectcalico/calico/v3.26.0/manifests/custom-resources.yaml

(Optional modification) If you used a pod-network-cidr other than 192.168.0.0/16,

edit custom-resources.yaml using nano to alter the "cidr:" line inside to match it.

Apply the custom network layout manifest

kubectl create -f custom-resources.yaml

<div class="code-block ng-tns-c1605810258-285 ng-animate-disabled ng-trigger ng-trigger-codeBlockRevealAnimation" id="bkmrk--19"><div class="formatted-code-block-internal-container ng-tns-c1605810258-285"><div class="animated-opacity ng-tns-c1605810258-285"></div></div></div>## 4. Join Worker Nodes (Execute on WORKER Nodes Only)

Move over to your designated worker VMs. Take the output you preserved from Step 3.1 and execute it with administrative flags:

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sudo kubeadm join <master-node-ip>:6443 --token <token-string> \
    --discovery-token-ca-cert-hash sha256:<hash-string>

### Missing your join token string?

If you ever lose the string or it expires (tokens automatically timeout after 24 hours), generate a brand-new execution block by running this command back on the Master node:

Bash

``` kubeadm token create --print-join-command ```