How to Install Kubernetes Cluster on CentOS 7

Admin April 17, 2023
How to Install Kubernetes Cluster on CentOS 7

Kubernetes is a powerful open-source platform that helps in automating deployment, scaling, and management of containerized applications. It is designed to be portable across different infrastructure providers and supports a wide range of container runtimes. In this article, we will learn how to install Kubernetes Cluster on CentOS 7.

Prerequisites:

Before we begin, let's make sure that the following prerequisites are met:

  • CentOS 7 installed on all the nodes that will form the Kubernetes cluster.
  • Each node should have at least 2GB of RAM and 2 CPU cores.
  • All the nodes should have a unique hostname and IP address.
  • All the nodes should have Docker installed.

Table of Contents

  1. Update System Packages
  2. Install Kubernetes Components
  3. Initialize Kubernetes Master
  4. Join Worker Nodes to Kubernetes Cluster
  5. Verify Kubernetes Cluster Installation

Commands:

Throughout this article, we will be using several commands. Make sure to run these commands with root privileges. To switch to the root user, run the following command:

sudo su -

Step-by-step Instructions:

  1. Update System Packages:

Before we start installing Kubernetes, we need to make sure that all the system packages are up-to-date. Run the following command to update all the system packages:
yum update -y

  1. Install Kubernetes Components:

We will now install Kubernetes components on all the nodes of the cluster. Run the following command to install the necessary packages:
yum install -y kubelet kubeadm kubectl

  1. Initialize Kubernetes Master:

The next step is to initialize the Kubernetes master. Run the following command on the master node:
kubeadm init --pod-network-cidr=192.168.0.0/16

This will install and configure all the necessary components of Kubernetes on the master node.

  1. Join Worker Nodes to Kubernetes Cluster:

Now, we need to join the worker nodes to the Kubernetes cluster. Run the command displayed in the output of the previous command on each worker node.
kubeadm join <master-node-ip>:<master-node-port> --token <token> --discovery-token-ca-cert-hash sha256:<hash>

  1. Verify Kubernetes Cluster Installation:

Finally, we need to verify if the Kubernetes cluster is installed and configured properly. Run the following command on the master node:
kubectl get nodes

This should display all the nodes that are part of the Kubernetes cluster.

More Examples:

In addition to the above steps, we can also install a network plugin to enable communication between the pods in the cluster. We will install the Calico network plugin using the following command:

kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/rbac-kdd.yaml
kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml

This will install the Calico network plugin on the Kubernetes cluster.

In this article, we learned how to install Kubernetes Cluster on CentOS 7. We covered the prerequisites, necessary commands, and step-by-step instructions to install and configure the Kubernetes cluster. We also learned how to verify the installation and install a network plugin. Kubernetes is a powerful platform that can help in deploying and managing containerized applications at scale.

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    • That's it for this post. Keep practicing and have fun. Leave your comments if any.

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