Install Kubernetes Using Containerd And Kubeadm On Ec2 Instances

In this exercise, you will need to spin up 3 EC2 instances, one will serve as your control plane or master node, and the other two will Servers, as your worker nodes.

Ensure that your master nodes are of high capacity, this lab uses an EC2 instance of the following capacities - Ubuntu, 20.04 LTS, t2.large.

Once your instances are ready, connect to your EC2 instances and set the hostname using the command. Setting hostname is for easy identification of the servers.


sudo hostnamectl set-hostname <choosen-hostname> 
sudo vi /etc/hosts

Edit the hostfile and map the hostname to the private IP of your servers across both the control plane server and worker nodes

Install Packages

Create the configuration file for containerd:

 cat <<EOF | sudo tee /etc/modules-load.d/containerd.conf
 overlay
 br_netfilter
 EOF

Load the modules:

 sudo modprobe overlay
 sudo modprobe br_netfilter

Set the system configurations for Kubernetes networking:

 cat <<EOF | sudo tee /etc/sysctl.d/99-kubernetes-cri.conf
 net.bridge.bridge-nf-call-iptables = 1
 net.ipv4.ip_forward = 1
 net.bridge.bridge-nf-call-ip6tables = 1
 EOF

Apply the new settings and reload the configuration:
```
 sudo sysctl --system
```

Install containerd:

 sudo apt-get update && sudo apt-get install -y containerd

Create the default configuration file for containerd:
```
 sudo mkdir -p /etc/containerd
```
Generate the default containerd configuration, and save it to the newly created default file:
```
 sudo containerd config default | sudo tee /etc/containerd/config.toml
```
Restart containerd to ensure the new configuration file is used:
```
 sudo systemctl restart containerd
```
Verify that containerd is running:
```
sudo systemctl status containerd
```
Disable swap:
```
sudo swapoff -a
```

Install the dependency packages:

sudo apt-get update && sudo apt-get install -y apt-transport-https curl

Download and add the GPG key:

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

Add Kubernetes to the repository list:

cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF

Update the package listings:
```
sudo apt-get update
```
Install Kubernetes packages:

Note: If you get a dpkg lock message, just wait a minute or two before trying the command again. Kindly install the lastest version instead of V1.27.0-00
```
sudo apt-get install -y kubelet=1.27.0-00 kubeadm=1.27.0-00 kubectl=1.27.0-00
```

Turn off automatic updates:

sudo apt-mark hold kubelet kubeadm kubectl

Initialize your Cluster

Initialize the Kubernetes cluster on the master node using kubeadm:

 sudo kubeadm init --pod-network-cidr 192.168.50.0/16 --kubernetes-version 1.27.0

Set kubectl access:

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

Test access to the cluster:
```
 kubectl get nodes
```

Install the Calico Network Add-On

On the master node, install Calico Networking:

Always confirm from Calico official documentation the install command

 kubectl create -f https://raw.githubusercontent.com/projectcalico/calico/v3.26.3/manifests/tigera-operator.yaml

Check the status of the control plane node: you will need to allow it some time to ensure your nodes are ready before proceeding to add other nodes
```
 kubectl get nodes
```

Join the Worker Nodes in the Cluster

In the control plane node, create the token and copy the kubeadm join command:
```
  kubeadm token create --print-join-command
```
Note: This output will be used as the next command for the worker nodes

like this kubeadm join <masterip>:6443 --token 3d9o26.j5566e5u7 --discovery-token-ca-cert-hash sha256:38b879a36f37ed9
Copy the full output from the command from the master node, navigate to the worker node, and run it as a root example sudo kubeadm join <masterip>:6443 --token 3d9o26.j5566e5u7 --discovery-token-ca-cert-hash sha256:38b879a36f37ed9
```
 sudo kubeadm join...
```

In the control plane/master node, view the cluster status:

kubectl get nodes

Note: You may have to wait a few minutes to allow your nodes to become ready.

Possible Errors

This error shows off when trying to install Calico ()

The connection to the server 172.31.30.242:6443 was refused - did you specify the right host or port?

HOW I RESOLVED IT

Reboot the instance
Run this command

On a successful run, do kubectl get nodes to see if this resolved the error, then proceed to install Calico

sudo -i
swapoff -a
exit
strace -eopenat kubectl version

if this doesn't resolve the issue confirm firewall on your host may be active.

sudo systemctl status ufw

and disable it using

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sudo systemctl stop ufw