Setup a MicroK8s Kubernetes cluster

Overview

This project will setup a MicroK8s kubernetes cluster on three Ubuntu Server 20.04 LTS servers. Two are Raspberry Pi and one is running standard hardware.

Install Ubuntu Server 22.04 on standard hardware

Follow the referenced guide from Canonical to setup Ubuntu 22.04 on standard hardware

Install Ubuntu Server 22.04 on Raspberry Pi

Follow the referenced guide from Canonical to setup Ubuntu 22.04 on Raspberry Pi hardware

Configure Ubuntu Server base settings

Before installing any software or services on Ubuntu it’s good practice to setup the base server first.

Update Ubuntu to the latest release

sudo apt-get update && sudo apt-get upgrade

Enable UFW (firewall) Ubuntu 22.04 servers can use the UFW firewall to ensure only connections to certain services are allowed.

ufw app list

Applications can register their profiles with UFW upon installation. These profiles allow UFW to manage these applications by name. OpenSSH, the service that allows you to connect to your server, has a profile registered with UFW.

You can examine the list of installed UFW profiles by typing:

ufw app list
Output
Available applications:
  OpenSSH

You will need to make sure that the firewall allows SSH connections so that you can log into your server next time. Allow these connections by typing:

ufw allow OpenSSH

Now enable the firewall by typing:

ufw enable

Type y and press ENTER to proceed. You can see that SSH connections are still allowed by typing:

ufw status

Output
Status: active

To                         Action      From
--                         ------      ----
OpenSSH                    ALLOW       Anywhere
OpenSSH (v6)               ALLOW       Anywhere (v6)

The firewall is currently blocking all connections except for SSH. If you install and configure additional services, you will need to adjust the firewall settings to allow the new traffic into your server.

Install MicroK8s

Logon to the main server using SSH and use the following snap command to install MicroK8s.

sudo snap install microk8s --classic

If installed successfully then you’ll receive a message similar to this. Notice the version installed was the latest stable release.

$ microk8s (1.28/stable) v1.28.3 from Canonical✓ installed

Running this command will show you the status of MicroK8s and which addons are enabled/disabled.

$ sudo microk8s status
microk8s is running
high-availability: no
  datastore master nodes: 127.0.0.1:19001
  datastore standby nodes: none
addons:
  enabled:
    dns                  # (core) CoreDNS
    ha-cluster           # (core) Configure high availability on the current node
    helm                 # (core) Helm - the package manager for Kubernetes
    helm3                # (core) Helm 3 - the package manager for Kubernetes
  disabled:
    cert-manager         # (core) Cloud native certificate management
    cis-hardening        # (core) Apply CIS K8s hardening
    community            # (core) The community addons repository
    dashboard            # (core) The Kubernetes dashboard
    gpu                  # (core) Automatic enablement of Nvidia CUDA
    host-access          # (core) Allow Pods connecting to Host services smoothly
    hostpath-storage     # (core) Storage class; allocates storage from host directory
    ingress              # (core) Ingress controller for external access
    kube-ovn             # (core) An advanced network fabric for Kubernetes
    mayastor             # (core) OpenEBS MayaStor
    metallb              # (core) Loadbalancer for your Kubernetes cluster
    metrics-server       # (core) K8s Metrics Server for API access to service metrics
    minio                # (core) MinIO object storage
    observability        # (core) A lightweight observability stack for logs, traces and metrics
    prometheus           # (core) Prometheus operator for monitoring and logging
    rbac                 # (core) Role-Based Access Control for authorisation
    registry             # (core) Private image registry exposed on localhost:32000
    rook-ceph            # (core) Distributed Ceph storage using Rook
    storage              # (core) Alias to hostpath-storage add-on, deprecated

Configure kubectl

MicroK8s come pre-bundled with its version kubectl and can execute the native Kubernetes commands to inspect and work with the cluster.

sudo microk8s kubectl get all -n kube-system

To avoid using microk8s as a prefix while running kubectl commands, you can add an alias if you don’t have an existing installation of kubectl using the following command.

alias kubectl='sudo microk8s kubectl'

Now, you can execute kubectl commands directly without the prefix.

kubectl get nodes

MicroK8s Dashboard

Install the dashboard.

microk8s enable dashboard ingress

Viewing the Dashboard view it by first starting a port-forward:

microk8s kubectl port-forward -n kube-system service/kubernetes-dashboard 10443:443

View the dashboard using the URL https://localhost:10443. To log in, we need a token or the full kubeconfig:

Generate a token

$ microk8s kubectl create token default

Generate kubeconfig

$ microk8s config Copy Note that the cluster uses a self-signed certificate, which will cause web browser warnings.

References

Install Ubuntu Server

How to install Ubuntu Server on your Raspberry Pi

How to build a Raspberry Pi Kubernetes cluster using MicroK8s

Initial Server Setup with Ubuntu 22.04

How to Setup a MicroK8s Kubernetes Cluster on Ubuntu 22.04

Introduction to snaps

UFW Essentials: Common Firewall Rules and Commands

Deploy and Access the Kubernetes Dashboard