[Kubernetes] 클러스터에 노드 추가

클러스터 구축 후 토큰 값을 까먹거나 여러 요인들로 추가로 작업해줘야할 경우에 아래 과정으로 실시하면 된다.

Master 노드

• 토큰 값 조회

# kubeadm token list
TOKEN                     TTL         EXPIRES                USAGES                   DESCRIPTION                                                EXTRA GROUPS
19iege.6onflcvyh6yr7bqq   21h         2024-09-09T06:10:33Z   authentication,signing   The default bootstrap token generated by 'kubeadm init'.   system:bootstrappers:kubeadm:default-node-token

• token 값에는 만료 기간이 있기 때문에 위에서 token 값을 확인할 수 없다면 새로운 token을 생성해줘야함

$ kubeadm token create
$ kubeadm token list

• HASH 값 확인

# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed 's/^.* //'
7bbb39683373cc97842fdbadfbdd9a3d918aa070e5a3ddf154dac0965d03bc20

추가할 작업 노드

$ kubeadm join <192.168.0.10:6443> --token <Token 값> --discovery-token-ca-cert-hash sha256:<Hash 값>

• 예시

# kubeadm join 192.168.207.40:6443 --token 19iege.6onflcvyh6yr7bqq --discovery-token-ca-cert-hash sha256:7bbb39683373cc97842fdbadfbdd9a3d918aa070e5a3ddf154dac0965d03bc20
[preflight] Running pre-flight checks
        [WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.