Lab Exercise: Installing a Kubernetes Cluster

Follow these steps to install Kubernetes on Amazon Linux:

Prerequisites:

• An Amazon Linux instance (e.g., EC2 instance)

• Basic knowledge of Linux commands

Steps:

1. Disable SELinux:

   • Edit the SELinux configuration file:

     vi /etc/selinux/config

   • Change SELINUX to permissive and policy to targeted:

     SELINUX=permissive

2. Verify SELinux Status:

   • If SELinux is disabled, edit the configuration and reboot the server.

   • Otherwise, execute the command. This will change it from enforcing to permissive.

     setenforce permissive

3. Load Kernel Modules:

   • Execute the following commands:

     modprobe overlay
     modprobe br_netfilter

4. Make Kernel Modules Permanent:

   • Edit the file /etc/modules-load.d/containerd.conf and add the following lines:

     overlay
     br_netfilter

5. Configure sysctl Settings:

   • Create or edit the file /etc/sysctl.d/99-kubernetes-cri.conf:

   vi /etc/sysctl.d/99-kubernetes-cri.conf

   - Add the following lines:
   ```ini
   net.bridge.bridge-nf-call-iptables = 1
   net.ipv4.ip_forward = 1
   net.bridge.bridge-nf-call-ip6tables = 1

   • Apply the sysctl settings:

     sysctl --system

6. Disable Swap and Remove Fstab Entry:

   • Disable swap:

     swapoff -a

   • Remove the swap entry from /etc/fstab.

7. Add Kubernetes Repository:

   • Create or edit the file /etc/yum.repos.d/kubernetes.repo:

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

   - Add the following content:
   ```ini
   [kubernetes]
   name=Kubernetes
   baseurl=https://pkgs.k8s.io/core:/stable:/v1.29/rpm/
   enabled=1
   gpgcheck=1
   gpgkey=https://pkgs.k8s.io/core:/stable:/v1.29/rpm/repodata/repomd.xml.key
   exclude=kubelet kubeadm kubectl cri-tools kubernetes-cni

8. Install Kubernetes Components:

   • Install kubelet, kubeadm, and kubectl:

     yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes

   • Enable the kubelet service:

     systemctl enable kubelet
     systemctl start kubelet

   • Install containerd:

     yum install -y containerd 

9. Create Containerd Configuration:

   • Run the following command:

     containerd config default | sudo tee /etc/containerd/config.toml

   • Edit /etc/containerd/config.toml: search for the below string and modifiy it to true.

     SystemdCgroup = true

   • Start containerd service :

     systemctl status containerd
     systemctl start  containerd
     systemctl enable   containerd
     

10. Configure Node IP:

    • Edit /etc/default/kubelet:

      KUBELET_EXTRA_ARGS=--node-ip={{ node_ip }}

11. Initialize the Kubernetes Cluster:

    • Run the following command (replace {IP address of the server} with your server's IP):

      sudo kubeadm init --apiserver-advertise-address="{IP address of the server}" --apiserver-cert-extra-sans="{IP address of the server}" --node-name master --pod-network-cidr=192.168.0.0/24

References

• Kubernetes Installation

• Creating a cluster with kubeadm