Kubernetes - 쿠버네티스 다중 클러스터 구성하기

• master(control-plane)
• kube-system이 포함되어 있는 노드 → sudo kubeadm init 를 한 노드
• 현재 클러스터 상태를 사용자가 원하는 클러스터 상태로 조정해준다.
• 보통 멀티노드 구성 시 master는 kube-system 관련 컨테이너들만 운영하는걸 추천함
• kube-system → api-server, Scheduler, etcd 등

• worker(data-plane)
• 구축할 프로그램들이 워커에서 운영
• kubelet : worker 노드는 kubelet을 통해 master 노드와 통신한다.
• kube-proxy : IP 변환, 네트워크 통신 관리 등

멀티노드 구축

1. worker에서 master의 host 이름을 등록
• /etc/hosts

127.0.0.1 localhost

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

{Master Ip} {control-plane name}

 

2. master kubeadm 세팅
• kubeadm.yaml

// kubeadm.yaml
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: stable-1.24
controlPlaneEndpoint: mdl-control-plane:6443

• kubeadm init

  echo "127.0.0.1 mdl-control-plane" | sudo tee -a /etc/hosts
  sudo kubeadm init --config kubeadm.yaml
  
  mkdir -p "$HOME"/.kube
  sudo cp -i /etc/kubernetes/admin.conf "$HOME"/.kube/config
  sudo chown "$(id -u)":"$(id -g)" "$HOME"/.kube/config

  sudo systemctl restart kubelet.service

• kubeadm init에서 token 정보 조회가 가능하다

...
You can now join any number of control-plane nodes by copying certificate authorities
and service account keys on each node and then running the following as root:

  kubeadm join mdl-control-plane:6443 --token itfxow.uuomu945zd1mmri5 \
        --discovery-token-ca-cert-hash sha256:3c2b420c03205a600de56c6c2ae9826850d547f259c77151667514a37af96c2a \
        --control-plane 

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join mdl-control-plane:6443 --token itfxow.uuomu945zd1mmri5 \
        --discovery-token-ca-cert-hash sha256:3c2b420c03205a600de56c6c2ae9826850d547f259c77151667514a37af96c2a 

1. worker join
위 kubeadm join 토큰을 입력한다

ubuntu@ip-172-31-13-105:~/adc-manager$ sudo kubeadm join mdl-control-plane:6443 --token itfxow.uuomu945zd1mmri5 \
>         --discovery-token-ca-cert-hash sha256:3c2b420c03205a600de56c6c2ae9826850d547f259c77151667514a37af96c2a
[preflight] Running pre-flight checks
[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.

1. taint, tolerration 및 Cni 적용