Kubernetes : Remove Nodes2020/08/19 |
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Remove Nodes from existing Kubernetes Cluster.
This example is based on the environment like follows and remove a Node [node03.srv.world] from it.
-----------+---------------------------+--------------------------+-------------+
| | | |
eth0|10.0.0.30 eth0|10.0.0.51 eth0|10.0.0.52 |
+----------+-----------+ +-----------+----------+ +-----------+----------+ |
| [ dlp.srv.world ] | | [ node01.srv.world ] | | [ node02.srv.world ] | |
| Master Node | | Worker Node | | Worker Node | |
+----------------------+ +----------------------+ +----------------------+ |
|
------------------------------------------------------------------+-------------+
|
eth0|10.0.0.53
+-----------+----------+
| [ node03.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 DeamonSet # --delete-local-data ⇒ ignore pods that has emptyDir volumes # --force ⇒ also remove pods that was created as a pod, not as deployment or others root@dlp:~# kubectl drain node03.srv.world --ignore-daemonsets --delete-local-data --force node/node03.srv.world drained # verify a few minutes later root@dlp:~# kubectl get nodes node03.srv.world NAME STATUS ROLES AGE VERSION node03.srv.world Ready,SchedulingDisabled <none> 28m v1.18.8 # run delete method root@dlp:~# kubectl delete node node03.srv.world node "node03.srv.world" deletedroot@dlp:~# kubectl get nodes NAME STATUS ROLES AGE VERSION dlp.srv.world Ready master 166m v1.18.8 node01.srv.world Ready <none> 162m v1.18.8 node02.srv.world Ready <none> 161m v1.18.8 |
| [2] | On the removed Node, Reset kubeadm settings. |
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root@node03:~# 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
W0819 14:22:09.113836 20286 removeetcdmember.go:79] [reset] No kubeadm config, using etcd pod spec to get data directory
[reset] No etcd config found. Assuming external etcd
[reset] Please, manually reset etcd to prevent further issues
[reset] Stopping the kubelet service
[reset] Unmounting mounted directories in "/var/lib/kubelet"
[reset] Deleting contents of config directories: [/etc/kubernetes/manifests /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]
[reset] Deleting contents of stateful directories: [/var/lib/kubelet /var/lib/dockershim /var/run/kubernetes /var/lib/cni]
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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