How to Install Kubernetes Cluster on Ubuntu 22.04

Are you looking for an easy guide on how to install Kubernetes Cluster on Ubuntu 22.04 (Jammy Jellyfish)?

The step-by-step guide on this page will show you how to install Kubernetes cluster on Ubuntu 22.04 using Kubeadm command step by step.

Kubernetes is a free and open-source container orchestration tool, it also known as k8s. With the help of Kubernetes, we can achieve automated deployment, scaling and management of containerized application.

A Kubernetes cluster consists of worker nodes on which application workload is deployed and a set up master nodes which are used to manage worker nodes and pods in the cluster.

In this guide, we are using one master node and two worker nodes. Following are system requirements on each node,

  • Minimal install Ubuntu 22.04
  • Minimum 2GB RAM or more
  • Minimum 2 CPU cores / or 2 vCPU
  • 20 GB free disk space on /var or more
  • Sudo user with admin rights
  • Internet connectivity on each node

Lab Setup

  • Master Node:  192.168.1.173 – k8smaster.example.net
  • First Worker Node:  192.168.1.174 – k8sworker1.example.net
  • Second Worker Node:  192.168.1.175 – k8sworker2.example.net

Without any delay, let’s jump into the installation steps of Kubernetes cluster

Step 1) Set hostname and add entries in the hosts file

Login to to master node and set hostname using hostnamectl command,

$ sudo hostnamectl set-hostname "k8smaster.example.net"
$ exec bash

On the worker nodes, run

$ sudo hostnamectl set-hostname "k8sworker1.example.net"   // 1st worker node
$ sudo hostnamectl set-hostname "k8sworker2.example.net"   // 2nd worker node
$ exec bash

Add the following entries in /etc/hosts file on each node

192.168.1.173   k8smaster.example.net k8smaster
192.168.1.174   k8sworker1.example.net k8sworker1
192.168.1.175   k8sworker2.example.net k8sworker2

Step 2) Disable swap & add kernel settings

Execute beneath swapoff and sed command to disable swap. Make sure to run the following commands on all the nodes.

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

Load the following kernel modules on all the nodes,

$ sudo tee /etc/modules-load.d/containerd.conf <<EOF
overlay
br_netfilter
EOF
$ sudo modprobe overlay
$ sudo modprobe br_netfilter

Set the following Kernel parameters for Kubernetes, run beneath tee command

$ 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 

Reload the above changes, run

$ sudo sysctl --system

Step 3) Install containerd run time

In this guide, we are using containerd run time for our Kubernetes cluster. So, to install containerd, first install its dependencies.

$ sudo apt install -y curl gnupg2 software-properties-common apt-transport-https ca-certificates

Enable docker repository

$ sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmour -o /etc/apt/trusted.gpg.d/docker.gpg
$ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

Now, run following apt command to install containerd

$ sudo apt update
$ sudo apt install -y containerd.io

Configure containerd so that it starts using systemd as cgroup.

$ containerd config default | sudo tee /etc/containerd/config.toml >/dev/null 2>&1
$ sudo sed -i 's/SystemdCgroup \= false/SystemdCgroup \= true/g' /etc/containerd/config.toml

Restart and enable containerd service

$ sudo systemctl restart containerd
$ sudo systemctl enable containerd

Step 4) Add apt repository for Kubernetes

Execute following commands to add apt repository for Kubernetes

$ curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
$ sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"

Note: At time of writing this guide, Xenial is the latest Kubernetes repository but when repository is available for Ubuntu 22.04 (Jammy Jellyfish) then you need replace xenial word with ‘jammy’ in ‘apt-add-repository’ command.

Step 5) Install Kubernetes components Kubectl, kubeadm & kubelet

Install Kubernetes components like kubectl, kubelet and Kubeadm utility on all the nodes. Run following set of commands,

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

Step 6) Initialize Kubernetes cluster with Kubeadm command

Now, we are all set to initialize Kubernetes cluster. Run the following Kubeadm command from the master node only.

$ sudo kubeadm init --control-plane-endpoint=k8smaster.example.net

Output of above command,

Kubeadm-initialize-kubernetes-ubuntu-22-04

As the output above confirms that control-plane has been initialize successfully. In output also we are getting set of commands for interacting the cluster and also the command for worker node to join the cluster.

So, to start interacting with cluster, run following commands from the master node,

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

Now, try to run following kubectl commands to view cluster and node status

$ kubectl cluster-info
$ kubectl get nodes

Output,

Initial-k8s-cluster-information

Join both the worker nodes to the cluster, command is already there is output, just copy paste on the worker nodes,

$ sudo kubeadm join k8smaster.example.net:6443 --token vt4ua6.wcma2y8pl4menxh2 \
   --discovery-token-ca-cert-hash sha256:0494aa7fc6ced8f8e7b20137ec0c5d2699dc5f8e616656932ff9173c94962a36

Output from both the worker nodes,

Woker1-Join-kubernetes-Cluster

Woker2-Join-kubernetes-Cluster

Check the nodes status from master node using kubectl command,

$ kubectl get nodes

Node-Status-K8s-Before-CNI

As we can see nodes status is ‘NotReady’, so to make it active. We must install CNI (Container Network Interface) or network add-on plugins like Calico, Flannel and Weave-net.

Step 6) Install Calico Pod Network Add-on

Run following curl and kubectl command to install Calico network plugin from the master node,

$ curl https://projectcalico.docs.tigera.io/manifests/calico.yaml -O
$ kubectl apply -f calico.yaml

Output of above commands would look like below,

Install-Calico-Network-Add-on-k8s

Verify the status of pods in kube-system namespace,

$ kubectl get pods -n kube-system

Output,

Kube-System-Pods-after-calico-installation

Perfect, check the nodes status as well.

$ kubectl get nodes

Nodes-Status-after-Calico-Network-Add-on

Great, above confirms that nodes are active node. Now, we can say that our Kubernetes cluster is functional.

Step 7) Test Kubernetes Installation

To test Kubernetes installation, let’s try to deploy nginx based application and try to access it.

$ kubectl create deployment nginx-app --image=nginx --replicas=2

Check the status of nginx-app deployment

$ kubectl get deployment nginx-app
NAME        READY   UP-TO-DATE   AVAILABLE   AGE
nginx-app   2/2     2            2           68s
$

Expose the deployment as NodePort,

$ kubectl expose deployment nginx-app --type=NodePort --port=80
service/nginx-app exposed
$

Run following commands to view service status

$ kubectl get svc nginx-app
$ kubectl describe svc nginx-app

Output of above commands,

Deployment-Service-Status-k8s

Use following command to access nginx based application,

$ curl http://<woker-node-ip-addres>:31246

$ curl http://192.168.1.174:31246

Output,

Curl-Command-Access-Nginx-Kubernetes

Great, above output confirms that nginx based application is accessible.

That’s all from this guide, I hope you have found this guide useful. Kindly do post your queries and feedback in below comments section.

Also Read: How to Configure Static IP Address on Ubuntu 22.04 LTS

18 thoughts on “How to Install Kubernetes Cluster on Ubuntu 22.04”

  1. after going through 100s of videos and different blog post , finally your document helped me to setup working kubernetes cluster….kudoz

    Reply
  2. The commands adding keys for the apt repos should be changed to something like this:

    sudo curl -fsSL ‘https://download.docker.com/linux/ubuntu/gpg’ | sudo gpg –dearmour -o /etc/apt/trusted.gpg.d/docker.gpg

    Reply
    • Hi Niels,

      Thanks for sharing the updated command. As per your suggestion, I have modified command in article as well.

      Reply
  3. Hi Niels, when running the “kubeadm init” or “kubeadm join” i had this error

    [preflight] Running pre-flight checks
    [WARNING SystemVerification]: missing optional cgroups: blkio
    error execution phase preflight: [preflight] Some fatal errors occurred:
    [ERROR FileContent–proc-sys-net-ipv4-ip_forward]: /proc/sys/net/ipv4/ip_forward contents are not set to 1
    [preflight] If you know what you are doing, you can make a check non-fatal with `–ignore-preflight-errors=…`

    To solve it, i had to set ip_forward content with 1 by following command:

    echo 1 > /proc/sys/net/ipv4/ip_forward

    Reply
  4. I currently have Ubuntu 22.04 installed, and I am planning on installing GitLab. I’d want to have a possibly basic Kubernetes environment. I am quite used to kubecti, but I am not confident whether to use MicroK8s, Rancher, MiniKube, or something else. Do you have any opinion about my situation? Thank you so much for answering.

    Reply
  5. This is a great tutorial, thank you for putting it together! I have managed to successfully create a cluster using it, which is awesome! Really appreciate the time you’ve taken here.

    Reply
  6. I don’t know why my pods is having crash status on calico

    [email protected]:~# kubectl get pods -n kube-system -o wide
    NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
    calico-kube-controllers-798cc86c47-g95km 1/1 Running 0 6m54s 172.16.16.129 k8smaster
    calico-node-2jwsx 1/1 Running 0 6m54s 192.168.60.10 k8smaster
    calico-node-5w2bj 0/1 Init:CrashLoopBackOff 5 (2m34s ago) 6m54s 192.168.60.11 k8sworker1
    calico-node-8rqx5 0/1 Init:CrashLoopBackOff 6 (22s ago) 6m54s 192.168.60.12 k8sworker2

    Reply

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