Install kubernetes cluster on Ec2 by using kubeadm

kubeadm is a command-line tool for simplifying the process of creating and managing Kubernetes clusters. It helps with cluster initialization, node joining, configuration management, upgrades, and adheres to secure defaults, making it easier for users to set up Kubernetes environments.

Here are some key features and functions of kubeadm:

1. Cluster Initialization: kubeadm can be used to initialize the control plane (master) node of a Kubernetes cluster. It sets up the necessary components like the API server, etcd, and controller manager with default configurations.

2. Node Joining: After initializing the control plane, kubeadm provides a command for worker nodes to join the cluster. This command contains the necessary authentication tokens and certificates required for secure communication with the master node.

3. Configuration Management: kubeadm generates the initial Kubernetes configuration files, including the kubeconfig files for kubectl. This simplifies the process of configuring kubectl to interact with the cluster.

4. Network Plugin Integration: kubeadm can be combined with various network plugins or add-ons to enable pod communication within the cluster. It often suggests popular network plugins like Calico, Flannel, or Weave.

5. Upgrades and Downgrades: kubeadm provides commands and features for upgrading and downgrading a Kubernetes cluster. This makes it easier to perform version updates of Kubernetes.

6. Customization: While kubeadm offers default configurations for cluster initialization, it also allows advanced users to customize the setup by providing configuration files for various components.

7. Secure Defaults: kubeadm is designed with security in mind and sets up the cluster with secure defaults, such as using certificates for authentication and enabling RBAC (Role-Based Access Control) by default.

8. Ease of Use: It aims to simplify the cluster setup process, making it accessible to users who may not have deep knowledge of Kubernetes internals.

   Both Master & Worker Node

   Run the following commands on both the master and worker nodes to prepare them for kubeadm.

    # using 'sudo su' is not a good practice.
    sudo apt update
    sudo apt-get install -y apt-transport-https ca-certificates curl
    sudo apt install docker.io -y
   
    sudo systemctl enable --now docker # enable and start in single command.
   
    # Adding GPG keys.
    curl -fsSL "https://packages.cloud.google.com/apt/doc/apt-key.gpg" | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/kubernetes-archive-keyring.gpg
   
    # Add the repository to the sourcelist.
    echo 'deb https://packages.cloud.google.com/apt kubernetes-xenial main' | sudo tee /etc/apt/sources.list.d/kubernetes.list
   
    sudo apt update 
    sudo apt install kubeadm=1.20.0-00 kubectl=1.20.0-00 kubelet=1.20.0-00 -y
   

ON Worker node repeat the same steps.

Master Node

1. Initialize the Kubernetes master node.

    sudo kubeadm init
   

   

Set up local kubeconfig (both for root user and normal user):

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Apply Weave network:

kubectl apply -f https://github.com/weaveworks/weave/releases/download/v2.8.1/weave-daemonset-k8s.yaml

Generate a token for worker nodes to join:

sudo kubeadm token create --print-join-command

1. Expose port 6443 in the Security group for the Worker to connect to Master Node:

   

On worker node:

Run the following commands on the worker node.

sudo kubeadm reset pre-flight checks

Paste the join command you got from the master node and append --v=5 at the end. Make sure either you are working as sudo user or use sudo before the command.

Now on master node:

Thank you