Kubernetes : Remove Nodes2023/07/28 |
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Remove Nodes from existing Kubernetes Cluster. This example is based on the environment like follows and remove a Node [snode03.srv.world] from it.
-----------+---------------------------+--------------------------+--------------+
| | | |
eth0|10.0.0.25 eth0|10.0.0.71 eth0|10.0.0.72 |
+----------+-----------+ +-----------+-----------+ +-----------+-----------+ |
| [ ctrl.srv.world ] | | [snode01.srv.world] | | [snode02.srv.world] | |
| Control Plane | | Worker Node | | Worker Node | |
+----------------------+ +-----------------------+ +-----------------------+ |
|
------------+--------------------------------------------------------------------+
|
eth0|10.0.0.73
+-----------+-----------+
| [snode03.srv.world] |
| Worker Node |
+-----------------------+
|
| [1] | Remove a Node on Master Node. |
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# prepare to remove a target node # --ignore-daemonsets ⇒ ignore pods in DaemonSet # --delete-emptydir-data ⇒ ignore pods that has emptyDir volumes # --force ⇒ also remove pods that was created as a pod, not as deployment or others root@ctrl:~# kubectl drain snode03.srv.world --ignore-daemonsets --delete-emptydir-data --force Warning: ignoring DaemonSet-managed Pods: kube-system/calico-node-b9xkk, kube-system/kube-proxy-86p6p node/snode03.srv.world drained # verify a few minutes later root@ctrl:~# kubectl get nodes snode03.srv.world NAME STATUS ROLES AGE VERSION snode03.srv.world Ready,SchedulingDisabled <none> 6m4s v1.26.6 # run delete method root@ctrl:~# kubectl delete node snode03.srv.world node "snode03.srv.world" deletedroot@ctrl:~# kubectl get nodes NAME STATUS ROLES AGE VERSION ctrl.srv.world Ready control-plane 5h49m v1.26.6 snode01.srv.world Ready <none> 56m v1.26.6 snode02.srv.world Ready <none> 56m v1.26.6 |
| [2] | On the removed Node, Reset kubeadm settings. |
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root@snode03:~# 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.
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