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Md.Shalahur Rahman
Md.Shalahur Rahman

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How to Create Kubernetes(K8s) Cluster Home Lab using Ubuntu Server 24.04

#kubernetes #docker #ubuntu #devops

A Kubernetes cluster is a set of nodes(computer or VM) that run containerized applications. It provides scalability, high availability, and automation for deployments.

To build the K8s cluster home lab we use two nodes. one is a master node called kb1 and another is a worker node called kb2.

Node configuration:

  • Cpu: 2
  • Memory: 3GB
  • Storage: 20GB

Node Ip:

  • kb1(master node): 192.168.0.112
  • kb2(worker node): 192.168.0.113

Note: Make sure ssh operation between two nodes is working

Let's start configuration:

Step 1: For all nodes
Change the hostname(optional) and update the host file for network communication.

To change hostname:

sudo hostnamectl set-hostname "<new-host-name>"
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Example:

sudo hostnamectl set-hostname "kb1"
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Add the IP and hostname mapping on each node to update the network communication.

Edit host file

cd  /etc/hosts
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Then add the mapping

<IP> <Hostname>
<IP> <Hostname>
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Example:

192.168.0.112  kb1
192.168.0.113  kb2
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Step 2: For all nodes
Disable the Swap and Load Kernel Modules

sudo swapoff -a && sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab
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To load the kernel modules using modprobe.

sudo modprobe overlay && sudo modprobe br_netfilter
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To permanently load these modules, create the file with the following content.

sudo tee /etc/modules-load.d/k8s.conf <<EOF
overlay
br_netfilter
EOF
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Next, add the kernel parameters like IP forwarding. Create a file and load the parameters using sysctl command.

sudo tee /etc/sysctl.d/kubernetes.conf <<EOT
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
EOT
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To load the above kernel parameters

sudo sysctl --system
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Step 3: For all nodes
Install Containerd

First, install containerd dependencies,

sudo apt install -y curl gnupg2 software-properties-common apt-transport-https ca-certificates
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Next, add containerd repository

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

sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
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Now, install containerd.

sudo apt update && sudo apt install containerd.io -y
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Configure containerd so that it starts using SystemdCgroup.

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
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Restart the containerd, to see the effect.

sudo systemctl restart containerd
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To check the status of containerd.

sudo systemctl status containerd
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Output:

● containerd.service - containerd container runtime
     Loaded: loaded (/usr/lib/systemd/system/containerd.service; enabled; preset: enabled)
     Active: active (running) since Mon 2025-02-17 16:20:34 UTC; 2h 17min ago
       Docs: https://containerd.io
    Process: 738 ExecStartPre=/sbin/modprobe overlay (code=exited, status=0/SUCCESS)
   Main PID: 741 (containerd)
      Tasks: 156
     Memory: 201.3M (peak: 229.5M)
        CPU: 20min 13.594s
     CGroup: /system.slice/containerd.service
             ├─  741 /usr/bin/containerd
             ├─ 1138 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 53e05d7bda37772f5869ec026de03b40d4ce532ba0303c42be5184994439b3bf -address /run/containerd/containerd.sock
             ├─ 1139 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 5398ebda2355cad57be69e19bf098e4202fe259a61270ea9cc274b81f77977ab -address /run/containerd/containerd.sock
             ├─ 1140 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id e4f1f987a5fb8db03db049b518fdfe6680b8c83617733de91620948c6bc00c95 -address /run/containerd/containerd.sock
             ├─ 1150 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 24d231aefec7bde2646ae123758907e5d464973705d8c0cd9d8db67756c19ef2 -address /run/containerd/containerd.sock
             ├─ 1547 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 4d7ddac790ef53cb30823d45ed4b675d54cf66694833158f8d15f0ba93b93e2c -address /run/containerd/containerd.sock
             ├─ 2267 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 72b50ae3cea036f3b51e18bf9b900ccd46399fed052bf51a41bcea735062f413 -address /run/containerd/containerd.sock
             ├─ 2377 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 2fcb5f2766fc1ff28a8a020c10eb1aff4b1895eb7ade8af65c72bedd0a634ead -address /run/containerd/containerd.sock
             ├─ 2434 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id d6f43f441495e4a00387114d5d7462bc54b1a592bd41bc1ee1709d16d507633b -address /run/containerd/containerd.sock
             └─27675 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 2b645f1523cda54eb099d35542d77347071c2cdaef648a7e5559ec01779bac29 -address /run/containerd/containerd.sock
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Step 4: For all nodes
Add kubernetes package repository

K8s packages are not available in the default package repositories of Ubuntu 24.04, so first we need to add the repository.

First, download the public signing key for the Kubernetes package repository using the curl command.

curl -fsSL https://pkgs.k8s.io/core:/stable:/v1.30/deb/Release.key | sudo gpg --dearmor -o /etc/apt/keyrings/k8s.gpg
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Next, add the repository

echo 'deb [signed-by=/etc/apt/keyrings/k8s.gpg] https://pkgs.k8s.io/core:/stable:/v1.31/deb/ /' | sudo tee /etc/apt/sources.list.d/k8s.list
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Step 5: For all nodes
Install K8s components like Kubeadm, Kubelet, and Kubectl to manage the Kubernetes cluster.

sudo apt update
sudo apt install kubelet kubeadm kubectl -y
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Step 6: For only master nodes
Initialize the Kubernetes Cluster

To initialize the control plane or master node using Kubeadm.

sudo kubeadm init --control-plane-endpoint=<master-node-name>
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Example:

sudo kubeadm init --control-plane-endpoint=kb1
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Output:

enable all user for k8s

As per instruction, run the following commands.

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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Step 7: For only worker nodes
Join Worker Nodes to master node

Add worker nodes to your Kubernetes cluster using the token generated during initialization.

worker node join hash
Example:

sudo kubeadm join 192.168.0.112:6443 --token yagkiy.650e76uk72jycv1k --discovery-token-ca-cert-hash sha256:2f01622e81717582443eac4f206436e7e3bd018e2f23e4197906c22c38df9f14
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Now head back to the master node and run

kubectl get nodes
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Output:

NAME   STATUS   ROLES           AGE   VERSION
kb1    NotReady    control-plane   10d   v1.31.5
kb2    NotReady    <none>          10d   v1.31.5
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The node status is NotReady. To change it to Ready we need to install the Calico network add-on plugin.

Step 8: For only master nodes
Install the Calico Network Plugin

kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.28.2/manifests/calico.yaml
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After the successful installation of the calico, the node status will change to Ready. To check run the below command.

kubectl get pods -n kube-system
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Output:

NAME                                      READY   STATUS    RESTARTS      AGE
calico-kube-controllers-b8d8894fb-rz6zx   1/1     Running   3 (24h ago)   7d21h
calico-node-4klgg                         1/1     Running   0             24h
calico-node-9c9lg                         1/1     Running   0             24h
coredns-7c65d6cfc9-8f26s                  1/1     Running   3 (24h ago)   7d21h
coredns-7c65d6cfc9-sgsvc                  1/1     Running   3 (24h ago)   7d21h
etcd-kb1                                  1/1     Running   4 (24h ago)   10d
kube-apiserver-kb1                        1/1     Running   4 (24h ago)   10d
kube-controller-manager-kb1               1/1     Running   9 (24h ago)   10d
kube-proxy-h5fnm                          1/1     Running   2 (25h ago)   10d
kube-proxy-n9zts                          1/1     Running   4 (24h ago)   10d
kube-scheduler-kb1                        1/1     Running   7 (24h ago)   10d
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Now, check the node status

kubectl get nodes
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Output:

NAME   STATUS   ROLES           AGE   VERSION
kb1    Ready    control-plane   10d   v1.31.5
kb2    Ready    <none>          10d   v1.31.5
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So, finally, we created the K8s cluster home lab successfully.

Step 9: Test K8s Installation

Create and expose an NGINX deployment to verify the setup.

To create a namespace

kubectl create ns <namespace-name>
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Example:

kubectl create ns demo-app
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To check whether the namespace was created or not

 kubectl get namespace
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Output

NAME              STATUS   AGE
default           Active   10d
demo-app          Active   10d
kube-node-lease   Active   10d
kube-public       Active   10d
kube-system       Active   10d
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To deploy nginx-app with two replica using the demo-app namespace

kubectl create deployment nginx-app --image nginx --replicas 2 --namespace demo-app
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To check whether the deployment was created or not

kubectl get deployment -n demo-app
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Output:

NAME        READY   UP-TO-DATE   AVAILABLE   AGE
nginx-app   2/2     2            2           9m55s
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To check whether the pods was created or not

kubectl get pods -n demo-app
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Output:

NAME                         READY   STATUS    RESTARTS   AGE
nginx-app-7df7b66fb5-9wkds   1/1     Running   0          9m37s
nginx-app-7df7b66fb5-xppqk   1/1     Running   0          9m37s
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To expose deployment

kubectl expose deployment nginx-app -n demo-app --type NodePort --port 80
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Output:

service/nginx-app exposed
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To check the running service

kubectl get svc -n demo-app
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Output:

NAME        TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
nginx-app   NodePort   10.110.254.203   <none>        80:31809/TCP   50s
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To access the nginx application using nodeport

curl http://<any-worker-IP>:<exposed-port>
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Example

curl http://192.168.0.113:31809
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Note: Do not mismatch the port number.
Output:

<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
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Top comments (2)

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shoyebahmed profile image
Shoyeb Ahmed Russel •

Nice hands on practice article.

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ratulsharker profile image
Ratul sharker •

Great article ❤️

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