Install Kubernetes on Rocky Linux 8, CentOS 8, and compatibles using kubeadm & CRI-O

** switch to root user before start **

sudo su -

Intro

This bash script is used to install Kubernetes on Rocky Linux 8 using kubeadm & CRI-O as a container runtime.

The file install.sh will configure each node and install the main components which are:

cri-o, kubelet, kubeadm, kubectl

Setup cluster nodes

To get started with installation download this repo and type the following commands:

chmode +x install.sh
bash install.sh

After installation, each node will reboot and then you can ignite the master node using kubeadm command:

kubeadm init

To start using your cluster, you need to run the following as a regular user:

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

You should now deploy a network plugin Pod to the cluster, for example, to use Calico network plugin use the following commands:

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

After pulling and spinning up master components images, the kubeadm init command will print the joining command that we will use on worker nodes which will be in the following syntax:

kubeadm join <ip-address>:6443\
--token=<token> \
--discovery-token-ca-cert-hash sha256:<ca-hash>

You can join any number of machines by running the previous command on each node as root.

To check if worker nodes joined the cluster type the following command

kubectl get nodes

Install MetalLB

To install MetalLB use the following commands:

kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.11.0/manifests/namespace.yaml
kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.11.0/manifests/metallb.yaml

Then use kubectl to apply the following configuration, it will gives MetalLB control over IPs from 192.168.1.240 to 192.168.1.250, and configures Layer 2 mode:

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: ConfigMap
metadata:
  namespace: metallb-system
  name: config
data:
  config: |
    address-pools:
    - name: default
      protocol: layer2
      addresses:
      - 192.168.1.240-192.168.1.250
EOF

Configure CRI-O with Docker Access token

To bypass Docker pull images policy, configure nodes to authenticate to a private registry:

cat <<EOF | tee -a /etc/crio/crio.conf
[crio.image]
global_auth_file="/etc/crio/config.json"
EOF

Then, in the following command, change the USERNAME & PASSWORD and apply it.

cat <<EOF | tee -a /etc/crio/config.json
{
    "auths": {
        "https://index.docker.io/v1/": {
            "auth": "$(echo -n "<USERNAME>:<PASSWORD>" | base64 -w0)"
        }
    }
}
EOF

Then reboot your system

shutdown -r now