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Kubernetes : ノードを削除する2023/07/28


既存の Kubernetes クラスターからノードを削除する場合は以下のように設定します。

以下のように 4 台のノードで構成している Kubernetes クラスターから [] ノードを削除します。

           |                           |                          |              |
       eth0|              eth0|             eth0|     |
+----------+-----------+   +-----------+-----------+   +-----------+-----------+ |
|  [ ]  |   |  []  |   |  []  | |
|     Control Plane    |   |      Worker Node      |   |      Worker Node      | |
+----------------------+   +-----------------------+   +-----------------------+ |
|  []  |
|      Worker Node      |

[1] Master ノードで対象ノードを削除します。
# 対象ノードを安全に削除するための事前準備
# --ignore-daemonsets ⇒ DeamonSet の Pod は無視
# --delete-emptydir-data ⇒ emptyDir ボリュームを持つ Pod は無視
# --force ⇒ 単体で作成された Pod も削除

kubectl drain --ignore-daemonsets --delete-emptydir-data --force

Warning: ignoring DaemonSet-managed Pods: kube-system/calico-node-b9xkk, kube-system/kube-proxy-86p6p
node/ drained

# 一定時間経過後に確認
# 時間は環境によって異なる

kubectl get nodes

NAME                STATUS                     ROLES    AGE    VERSION   Ready,SchedulingDisabled   <none>   6m4s   v1.26.6

# 削除処理を実行

kubectl delete node

node "" deleted

kubectl get nodes

NAME                STATUS   ROLES           AGE     VERSION      Ready    control-plane   5h49m   v1.26.6   Ready    <none>          56m     v1.26.6   Ready    <none>          56m     v1.26.6
[2] 削除したノードで、kubeadm の設定をリセットしておきます。
kubeadm reset

[reset] WARNING: Changes made to this host by 'kubeadm init' or 'kubeadm join' will be reverted.
[reset] Are you sure you want to proceed? [y/N]: y
[preflight] Running pre-flight checks
W0728 00:55:59.745953    5201 removeetcdmember.go:106] [reset] No kubeadm config, using etcd pod spec to get data directory
[reset] Deleted contents of the etcd data directory: /var/lib/etcd
[reset] Stopping the kubelet service
[reset] Unmounting mounted directories in "/var/lib/kubelet"
[reset] Deleting contents of directories: [/etc/kubernetes/manifests /var/lib/kubelet /etc/kubernetes/pki]
[reset] Deleting files: [/etc/kubernetes/admin.conf /etc/kubernetes/kubelet.conf /etc/kubernetes/bootstrap-kubelet.conf /etc/kubernetes/controller-manager.conf /etc/kubernetes/scheduler.conf]

The reset process does not clean CNI configuration. To do so, you must remove /etc/cni/net.d

The reset process does not reset or clean up iptables rules or IPVS tables.
If you wish to reset iptables, you must do so manually by using the "iptables" command.

If your cluster was setup to utilize IPVS, run ipvsadm --clear (or similar)
to reset your system's IPVS tables.

The reset process does not clean your kubeconfig files and you must remove them manually.
Please, check the contents of the $HOME/.kube/config file.