Best of 2023: Setting up Kubernetes in an On-Premises Environment

December 29, 2023December 28, 2023 Lucky Kumar Sappa bare metal, kubernetes, Kubernetes clusters, on-premises

As we close out 2023, we at Cloud Native Now wanted to highlight the most popular articles of the year. Following is the latest in our series of the Best of 2023.

Kubernetes plays a leading role in deploying applications across different platforms. This is a major step up compared to the traditional way of deploying applications and offers a more comprehensive way of achieving continuous integration (CI) and continuous deployment (CD) enabling robust resource management using Kubernetes API. This blog explains how to install and configure a Kubernetes cluster on bare metal (on-premises).

Prerequisites:

In this setup, we are using one master node and two worker nodes.

ISO image version: Ubuntu 20.04.2 LTS (all nodes)

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Virtual box/hypervisor: To deploy VM’s

Internet access

Hardware specifications:

Master node: RAM: 8GB, CPU-4

Worker nodes: RAM: 4GB each, CPU-2

Assuming that you created virtual machines with the above specifications, here are the steps for Kubernetes setup.

Docker installation:

Install Docker on all three machines

# sudo apt-get update

# apt-get install curl

# curl -fsSL get.docker.com -o get-docker.sh

# sudo sh get-docker.sh

# docker version

Update the hostnames in all the nodes for easy understanding of the environment.

# apt-get install vim

# apt-get update

# vi /etc/hosts

Get the IPs of all the nodes and save them in /etc/hosts on all the machines.

Then update the hostname in /etc/hostnames

Restart the machine for the changes to take effect.

Kubernetes Installation:

Follow the below commands step-by-step in master nodes:

# swapoff -a (this is used to turn off the swap memory in all the nodes)

# apt-get update && apt-get install -y apt-transport-https

# snap install kubelet –classic

# snap install kubectl –classic

# snap install kubeadm –classic

Now, check the status of Docker. It should be up and running on all the nodes.

# kubeadm init –pod-network-cidr=10.211.0.0/16

In case you have multiple master node interfaces and want to specify the IP address of the API server manually, you can define it using the following command.

# kubeadm init –pod-network-cidr=10.211.0.0/16 –apiserver-advertise-address=<Ip address of master node>

Once the cluster is initialized, we get the following message: “Your Kubernetes control-plane has initialized successfully!” as shown below. Save the join token in Notepad and execute it on all the worker nodes to connect to master.

To start using your cluster, you need to run the following commands on the master node.

# sudo mkdir -p $HOME/.kube

# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

# sudo chown $(id -u):$(id -g) $HOME/.kube/config

Alternatively, if you are the root user you can run:

# export KUBECONFIG=/etc/kubernetes/admin.conf

Then you can join any number of worker nodes by running the following on each worker node as root:

# kubeadm join 10.211.55.7:6443 –token r58v9e.fue165xq18n4tzxw \

–discovery-token-ca-cert-hash sha256:979e8898318e056047146cfc1132d6ca49e2e705b2b91c1b5cdfe9f55d3ed270

Now check the status of Kubernetes nodes by issuing the below command:

# kubectl get nodes –o wide

Here, when we are configuring the worker node to the master node, we may encounter an issue while adding the node. If that happens, we need to add the cgroup driver details as follows:

Change the cgroupdriver to systemd default and reload the Docker daemon (we are making this change as Kubernetes recommended cgroupdriver is system).

Add the following content /etc/docker/daemon.json:

$cat /etc/docker/daemon.json

{

“exec-opts”: [“native.cgroupdriver=systemd”],

“log-driver”: “json-file”,

“log-opts”: {

“max-size”: “100m”

“storage-driver”: “overlay2”

}

After making this change, reload and restart Docker on the master node.

# systemctl daemon-reload

# ßsystemctl restart docker