Building a Kubernetes 1.21 Cluster with Kubeadm

Introduction

This lab will allow you to practice the process of building a new Kubernetes cluster. You will be given a set of Linux servers, and you will have the opportunity to turn these servers into a functioning Kubernetes cluster. This will help you build the skills necessary to create your own Kubernetes clusters in the real world.

Solution

ssh cloud_user@<PUBLIC_IP_ADDRESS>

Install Packages

Log into the Control Plane Node (Note: The following steps must be performed on all three nodes.).

Create configuration file for containerd:

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

Load modules:

sudo modprobe overlay
sudo modprobe br_netfilter

Set 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 new settings:
```
sudo sysctl --system
```

Install containerd:

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

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

Disable swap on startup in:

/etc/fstab

sudo sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

Install dependency packages:

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

Download and add GPG key:

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

Add Kubernetes to repository list:

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

Update 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):
```
sudo apt-get install -y kubelet=1.21.0-00 kubeadm=1.21.0-00 kubectl=1.21.0-00
```

Turn off automatic updates:

sudo apt-mark hold kubelet kubeadm kubectl

Log into both Worker Nodes to perform previous steps.

Initialize the Cluster

Initialize the Kubernetes cluster on the control plane node using kubeadm
(Note: This is only performed on the Control Plane Node):
```
sudo kubeadm init --pod-network-cidr 192.168.0.0/16 --kubernetes-version 1.21.0
```

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 cluster:
```
kubectl get nodes
```

Install the Calico Network Add-On

On the Control Plane Node, install Calico Networking:

kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml

Check status of the control plane node:
```
kubectl get nodes
```

Join the Worker Nodes to the Cluster

In the Control Plane Node, create the token and copy the kubeadm join command
(NOTE:The join command can also be found in the output from kubeadm init command):
```
kubeadm token create --print-join-command
```
In both Worker Nodes, paste the kubeadm join command to join the cluster. Use sudo to run it as root:
```
sudo kubeadm join ...
```
In the Control Plane Node, view cluster status (Note: You may have to wait a few moments to allow all nodes to become ready):
```
kubectl get nodes
```

Building a Kubernetes 1.21 Cluster with Kubeadm¶

Introduction¶

Solution¶

Install Packages¶

Initialize the Cluster¶

Install the Calico Network Add-On¶

Join the Worker Nodes to the Cluster¶