CentOS Stream 10: Configure Control Plane Node

Configure Multi Nodes Kubernetes Cluster.

This example is based on the environment like follows.

+----------------------+   +----------------------+
|  [ ctrl.srv.world ]  |   |   [ dlp.srv.world ]  |
|     Manager Node     |   |     Control Plane    |
+-----------+----------+   +-----------+----------+
        eth0|10.0.0.25             eth0|10.0.0.30
            |                          |
------------+--------------------------+-----------
            |                          |
        eth0|10.0.0.51             eth0|10.0.0.52
+-----------+----------+   +-----------+----------+
| [ node01.srv.world ] |   | [ node02.srv.world ] |
|     Worker Node#1    |   |     Worker Node#2    |
+----------------------+   +----------------------+

Prerequisites

Configure pre-requirements on all Nodes as shown in Install Kubeadm.

Initialize Control Plane Node

Generate the default kubeadm configuration:

kubeadm config print init-defaults > config.yaml

Edit config.yaml:

apiVersion: kubeadm.k8s.io/v1beta4
bootstrapTokens:
- groups:
  - system:bootstrappers:kubeadm:default-node-token
  token: abcdef.0123456789abcdef
  ttl: 24h0m0s
  usages:
  - signing
  - authentication
kind: InitConfiguration
localAPIEndpoint:
  # change to specify Control Plane Node IP address
  advertiseAddress: 10.0.0.30
  bindPort: 6443
nodeRegistration:
  # change to specify CRI-O
  criSocket: unix:///var/run/crio/crio.sock
  imagePullPolicy: IfNotPresent
  imagePullSerial: true
  # change to specify Control Plane Node Hostname
  name: dlp.srv.world
  taints: null
---
apiVersion: kubeadm.k8s.io/v1beta4
caCertificateValidityPeriod: 87600h0m0s
certificateValidityPeriod: 8760h0m0s
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns: {}
encryptionAlgorithm: RSA-2048
etcd:
  local:
    dataDir: /var/lib/etcd
imageRepository: registry.k8s.io
kind: ClusterConfiguration
kubernetesVersion: 1.32.0
# specify the Manager Node IP address for proxying
controlPlaneEndpoint: "10.0.0.25:6443"
networking:
  dnsDomain: cluster.local
  serviceSubnet: 10.96.0.0/12
  # Calico default pod network
  podSubnet: 192.168.0.0/16
---
# switch to nftables kube-proxy
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
mode: nftables

Initialize the cluster:

kubeadm init --config=config.yaml

After initialization, set up kubeconfig:

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

Transfer the admin.conf to the Manager Node:

scp /etc/kubernetes/admin.conf centos@10.0.0.25:/tmp

Configure Pod Network with Calico

On the Manager Node, set up cluster admin access and deploy Calico:

mkdir -p $HOME/.kube
mv /tmp/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

wget https://raw.githubusercontent.com/projectcalico/calico/v3.30.2/manifests/operator-crds.yaml
wget https://raw.githubusercontent.com/projectcalico/calico/v3.30.2/manifests/tigera-operator.yaml

kubectl apply -f operator-crds.yaml
kubectl apply -f tigera-operator.yaml

Create custom resources for Calico:

cat > custom-resources.yaml <<EOF
apiVersion: operator.tigera.io/v1
kind: Installation
metadata:
  name: default
spec:
  calicoNetwork:
    linuxDataplane: Nftables
    ipPools:
    - name: default-ipv4-ippool
      blockSize: 26
      cidr: 192.168.0.0/16
      encapsulation: VXLANCrossSubnet
      natOutgoing: Enabled
      nodeSelector: all()
---
apiVersion: operator.tigera.io/v1
kind: APIServer
metadata:
  name: default
spec: {}
EOF

kubectl apply -f custom-resources.yaml

Verify the cluster status:

kubectl get nodes
kubectl get pods -A