Local Kubernetes Cluster with Multipass

Overview

Guide Information

Difficulty: Intermediate
Time Required: ~30 minutes
Last Updated: March 2024

Table of Contents

1. Setup Multipass
2. Provision Virtual Machines
3. Server Preparation
4. Configure System Settings
5. Install Kubernetes Components
6. Initialize Cluster
7. Setup Network Interface
8. Join Worker Nodes
9. Verify Cluster
10. Troubleshooting
11. Cluster Maintenance

Architecture

graph TD
    A[Host Ubuntu 24.04] --> B[Multipass]
    B --> C[Master Node<br/>4GB RAM, 2 CPU]
    B --> D[Worker1<br/>4GB RAM, 2 CPU]
    B --> E[Worker2<br/>4GB RAM, 2 CPU]
    C --> F[Control Plane]
    F --> G[API Server]
    F --> H[etcd]
    F --> I[Controller Manager]
    F --> J[Scheduler]
    D --> K[kubelet]
    D --> L[containerd]
    E --> M[kubelet]
    E --> N[containerd]

Setup Multipass

Quick Setup

Multipass provides a fast way to spin up Ubuntu VMs. It's lightweight and perfect for local Kubernetes clusters.

Install MultipassVerify InstallationList Available Images

sudo snap install multipass

multipass version

multipass find

Provision Virtual Machines

Resource Allocation

We'll create one master node and two worker nodes. Adjust the resources based on your system capabilities.

Create Cluster Nodes

# Create master node
multipass launch --name master --cpus 2 --mem 4G --disk 20G 

# Create worker nodes
multipass launch --name worker1 --cpus 2 --mem 4G --disk 20G 
multipass launch --name worker2 --cpus 2 --mem 4G --disk 20G 

Expected Output

Launched: master
Launched: worker1
Launched: worker2

Access Nodes

Master NodeWorker Node 1Worker Node 2

multipass shell master

multipass shell worker1

multipass shell worker2

Get Node IPs

multipass list

Server Preparation

Important

Run these commands on ALL nodes (master and workers).

Update SystemInstall DependenciesSetup Docker Repository

sudo apt update && sudo apt upgrade -y

sudo apt install -y apt-transport-https ca-certificates curl gnupg lsb-release

sudo mkdir -p /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo tee /etc/apt/keyrings/docker.asc > /dev/null
echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Install Containerd

# Install containerd
sudo apt update
sudo apt install -y containerd.io

# Enable and start containerd
sudo systemctl enable containerd
sudo systemctl start containerd

# Generate default config
sudo mkdir -p /etc/containerd
containerd config default | sudo tee /etc/containerd/config.toml

# Modify containerd configuration
sudo sed -i 's/SystemdCgroup = false/SystemdCgroup = true/' /etc/containerd/config.toml
sudo sed -i 's/^disabled_plugins = \["cri"\]/#disabled_plugins = \["cri"\]/' /etc/containerd/config.toml

# Restart containerd
sudo systemctl restart containerd

Configure System Settings

Critical Step

Skipping these configurations may result in cluster initialization failures.

Disable SwapLoad Kernel ModulesConfigure Sysctl

sudo swapoff -a
sudo sed -i '/swap/d' /etc/fstab

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

sudo modprobe overlay
sudo modprobe br_netfilter

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

Install Kubernetes Components

Version Information

This guide uses Kubernetes v1.32. Adjust version numbers as needed.

Install Kubernetes Tools

# Add Kubernetes repository
curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.32/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:/v1.32/deb/ /' | sudo tee /etc/apt/sources.list.d/kubernetes.list

# Install required packages
sudo apt update
sudo apt install -y kubelet kubeadm kubectl

# Prevent accidental upgrades
sudo apt-mark hold kubelet kubeadm kubectl

# Enable kubelet
sudo systemctl enable kubelet
sudo systemctl start kubelet

Initialize Cluster

Master Node Only

Run these commands ONLY on the master node.

Initialize Kubernetes Cluster

# Initialize cluster
sudo kubeadm init --pod-network-cidr=10.244.0.0/16

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

Save the Join Command

The initialization will output a kubeadm join command. Save this for joining worker nodes.

Setup Network Interface

Install Flannel CNIVerify Installation

kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml

kubectl get pods -n kube-flannel

Join Worker Nodes

Worker Nodes Only

Run these commands on each worker node.

Get Join Command (Master)Join Cluster (Workers)

kubeadm token create --print-join-command

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

Verify Cluster

Check Node StatusCheck Pods

kubectl get nodes

kubectl get pods -A

Troubleshooting

Common Issues

Node Not ReadyJoin Command IssuesPod Network Issues

1. Check CNI pods: kubectl get pods -n kube-system
2. Check kubelet status: systemctl status kubelet
3. View kubelet logs: journalctl -xeu kubelet

1. Generate new token: kubeadm token create
2. Get discovery token CA cert hash:

   openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | \
   openssl rsa -pubin -outform der 2>/dev/null | \
   openssl dgst -sha256 -hex | sed 's/^.* //'
   

1. Check flannel pods: kubectl get pods -n kube-flannel
2. Check flannel logs: kubectl logs -n kube-flannel <pod-name>

Cluster Maintenance

Backup Procedures

Backup etcd

sudo apt install etcd-client
ETCDCTL_API=3 etcdctl --endpoints=https://127.0.0.1:2379 \
--cacert=/etc/kubernetes/pki/etcd/ca.crt \
--cert=/etc/kubernetes/pki/etcd/server.crt \
--key=/etc/kubernetes/pki/etcd/server.key \
snapshot save snapshot.db

Scaling the Cluster

To add more worker nodes:

1. Create new VM using multipass
2. Follow server preparation steps
3. Join the cluster using the join command

Cleanup

Delete NodeDelete VM

# On master node
kubectl drain <node-name> --ignore-daemonsets
kubectl delete node <node-name>

# On worker node
sudo kubeadm reset

multipass delete <vm-name>
multipass purge

Security Best Practices

1. Keep Kubernetes version updated
2. Use Network Policies
3. Enable RBAC
4. Regularly rotate certificates
5. Monitor cluster with security tools

Next Steps

• Deploy sample applications
• Setup monitoring with Prometheus and Grafana
• Configure persistent storage
• Implement high availability

Need Help?

If you encounter any issues, check the official Kubernetes documentation or open an issue in the repository.