Introduction

Setting up a Kubernetes Cluster

There are several ways how to set up a Kubernetes Cluster. Find an example from the following chapters.

The basic step which can be followed to install the Kubernetes cluster on Centos are:

1. Install Docker on all CentOS 7 VMs

   1. Update the package database

      sudo yum check-update

   2. Install the dependencies

      sudo yum install -y yum-utils device-mapper-persistent-data lvm2

   3. Add and enable the official Docker Repository to CentOS 7

      sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

   4. Install the latest Docker version on CentOS 7

      sudo yum install docker-ce

      
      

      
      

   5. A successful installation output will be concluded with a Complete!
You may be prompted to accept the GPG key. This is to verify that the fingerprint matches. The format will look as follows. If correct, accept it.

      060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35

   6. Manage Docker service
      Now Docker is installed, but the service is not yet running. Start and enable Docker using the commands. 
      

      sudo systemctl start docker
      sudo systemctl enable docker

   7. To confirm that Docker is active and running use:
      

      sudo systemctl status docker

2. Set up the Kubernetes Repository

   1. Since the Kubernetes packages aren’t present in the official CentOS 7 repositories, we will need to add a new repository file. Use the following command to create the file and open it for editing:
      

      sudo vi /etc/yum.repos.d/kubernetes.repo

   2. Once the file is open, press I key to enter insert mode, and paste the following contents:
      

      [kubernetes]
      name=Kubernetes
      baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
      enabled=1
      gpgcheck=1
      repo_gpgcheck=1
      gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg

      Once pasted, press escape to exit insert mode. Then enter :x to save the file and exit.

      
      

3. Install Kubelet on CentOS 7

   1. The first core module that we need to install on every node is Kubelet. Use the following command to do so:
      

      sudo yum install -y kubelet

4. Install kubeadm and kubectl on CentOS 7

   1. kubeadm, the next core module, which has to be installed. Use the following command:

      sudo yum install -y kubeadm

      (Note that kubeadm automatically installs kubectl as a dependency)

      
      

Deployment Files

Deployment File

=> insert the example file

=> add explanations for specific settings

Service File

=> insert the example file

=> add explanations for specific settings