Setting up kubernetes using Kubeadm

Pre-requisites:

t2.medium AWS instance for master node
t2.micro AWS instance for worker node
Docker

Installation steps:

Follow the below steps on both the master and worker node

All the commands to be executed in super user mode(with root privileges)

Docker installation

We will use docker to containerize the application, so let's first download and install docker on both the master and worker node. To do this login as root user
```
 sudo su
 apt update -y
 apt-get install docker.io -y
 systemctl start docker
 systemctl enable docker
```

Downloading the required Kubernetes configuration

Follow the below steps on both master and worker nodes with root user privilege

Download the Google Cloud public signing key:

 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 Kubernetes apt repository:

 echo 'deb https://packages.cloud.google.com/apt kubernetes-xenial main' > /etc/apt/sources.list.d/kubernetes.list

Update apt package index, install kubelet, kubeadm and kubectl, and pin their version:

 apt update -y
 apt install kubeadm=1.20.0-00 kubectl=1.20.0-00 kubelet=1.20.0-00 -y

Setting up Kubernetes configuration

Master node configuration

Execute below commands on only the master node with root user privileges

Initialise kubeadm
```
 kubeadm init
```
Create .kube directory in the user's home path, which is needed to store Kubernetes configuration
```
 mkdir -p $HOME/.kube
```
Copy the Kubernetes cluster configuration file admin.conf to the .kube directory. The sudo prefix grants the necessary administrative privileges to access the /etc/kubernetes/ directory.
```
 sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
```
Change the ownership of the copied config file to the current user. This ensures the user has permission to access and modify the Kubernetes configuration.
```
 sudo chown $(id -u):$(id -g) $HOME/.kube/config
```

Setting upWeave Network CNI

This step also should be done on the master

Use kubectl to apply the Weave Network CNI configuration from the specified URL. The Weave Network CNI enables efficient communication between containers running on different nodes within the Kubernetes cluster.
```
 kubectl apply -f https://github.com/weaveworks/weave/releases/download/v2.8.1/weave-daemonset-k8s.yaml
```

Generating token

This step also should be done on master with root user privileges

Generate the token that we will use to join a worker node
```
 kubeadm token create --print-join-command
```
Copy the output of this command as we will be using this command to create a cluster

Creating worker node

This step also should be done on worker

Log in as the root user and pass the below commands
```
  sudo su
  kubeadm reset pre-flight checks
```
Open port no 6443 in the master's security group

Paste the join command on the worker node and append --v=5 at end

 kubeadm join 172.31.12.68:6443 --token 8v4u6j.zc7tuyp6gnr1wdqe     --discovery-token-ca-cert-hash sha256:c81d4fea2a6d61261723f45dd217b318101f86f2428b2c29572a666290a148ae --v=5

AND WE ARE JUST ONE STEP AWAY FROM COMPLETING THE SETUP

Now when you type kubectl get nodes in master, you can see that the Kubeadm setup is complete

Creating nginx pod:

Execute the below command in the master node to create an nginx pod

kubectl run nginx --image=nginx --restart=Never