[ Kube 17 ] Renaming Kubernetes Nodes

In this video I will show you how to rename Kubernetes nodes. This was a question asked by one of the viewer.
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[@shuaibtyagi1123]

I follow your videos. these are very very helpful. I really appreciate your efforts.

[@justmeandopensource]

Hi Shuaib, thanks for watching. Cheers.

[@HoodBoyNO1]

nice video and representation. Thanks!

[@justmeandopensource]

Hi Chero, thanks for watching

[@jamallmahmoudi9481]

Hi, venkat cool&perfect 🙏

[@justmeandopensource]

Hi Jamal, thanks for watching.

[@Siva-ur4md]

Thank you so much, I loved your immediate response....... Thank you so much Venkat.....

[@justmeandopensource]

Anytime. Thanks.

[@justmeandopensource]

And Happy new year!!

[@dom67911]

Pretty cool. Thanks!

[@justmeandopensource]

Hi Jose, you are welcome. Cheers.

[@romantsyupryk3009]

Thanks so much for this tutorial.

[@justmeandopensource]

Hi Roman, thanks for watching.

[@md.zakirhossain6210]

Nice and well explained.

[@justmeandopensource]

Hi Zakir, thanks for watching.

[@muradheyderov]

Thanks a lot Venkat

[@justmeandopensource]

Hi Murad, thanks for watching.

[@dom67911]

Ideas for videos: istio, calico, how to upgrade a cluster to a later version of k8s, multicluster setup, recovering when master is lost, intro to helm, and rbac. For intermediate viewers, creating your own k8s operators using operator framework, prometheus, zipkin, multi-cluster setup, alternatives to Docker (cri-o, rkt), best practices in POD definitions (e.g. resourcing, affinity).

[@justmeandopensource]

Hey Jose, many thanks for the list of topics. I didn't think of some of these topics and glad you brought it up. Once I complete the fundamental concepts, I will definitely cover these. Thanks again.

[@abdulshaikh6807]

Nice

[@justmeandopensource]

Thanks Abdul

[@MrDierme]

Thanks a lot! Was looking for the solution for a while. A shame that there is still no way to rename the node without deleting it.

[@justmeandopensource]

Hi Oleksii, thanks for watching. This is not a very common practise but I don't think there is anyother way.

[@RavindraKumarSG]

Great . What if the node to renamed is a master node ?

[@shashidharwl4322]

Hi Venkat, I was trying to change the Node name but it's EKS, the hostnames are changed and wanted to overide the node name, right now the nodes are in ready status after changing the hostnames but to avoid issues in future is there a way i can add custom hostnames to my nodes on AWS ?? can you try this and give an update please

[@justmeandopensource]

Hi Shashidhar, thanks for watching. I will give it a try when I find some time. But this was a hacky solution.

[@MrShashi546]

@@justmeandopensource can i send a private message, instead of public chat...let me know wanted to share my thoughts..

[@justmeandopensource]

@@MrShashi546 You can join the slack workspace for this channel where there are over 100 like minded people. Here is the invitation link. I try to answer most of the questions/comments. But unfortunately don't have the luxury of time. join.slack.com/t/justmeopensource/shared_invite/enQtODg4NDcxMTg5Mjk2LTgyNWJkMzlmNzRlMDdhYzc2ZjA3NjA0N2ZkODg5NzAyMzNjMGY4OGJjZDkzNmRhNDU1ZjEzZjc1NzhiMjBlMmI

[@VincentTubed]

Thank you for a very clear and useful tutorial. Any ideas on how to rename the master node too?

[@justmeandopensource]

Hi, thanks for watching. I haven't actually tried that. I think we can follow the same process but it is going to require a downtime for your cluster definitely unless you have multi master setup.

[@VincentTubed]

@@justmeandopensource yeah I understand. But since we reset and init, doesn't everything get removed? I guess some kind of backup procedure or new master is required or to go with : kubernetes.io/docs/setup/production-environment/tools/kubeadm/high-availability/ . Would be cool to see a video on that :).

[@justmeandopensource]

I will definitely take a look at that. But people prefer more automated approach when it comes to production deployment. They either go with managed kubernetes service or use tools like kops, kubespray which makes it easier to provision and manage a HA k8s cluster. I have done many videos on Kubespray. Cheers.

[@seiji42]

@@justmeandopensource If you could, it would be brilliant to see you make a video on a routine to back up, re-initialize (with a new name, preferably), and restore a kubernetes cluster master node.

[@justmeandopensource]

@@seiji42 Thanks for watching. I will explore those options and see if I can make a video. Cheers.

[@tsingh7491]

Hi Venkat, facing some issues when trying to add a new kworker3 to the existing cluster: ++ Using the adm join token from master, the kworker3 throws: KERNEL_VERSION: 5.3.0-40-generic DOCKER_VERSION: 19.03.5 DOCKER_GRAPH_DRIVER: overlay2 OS: Linux CGROUPS_CPU: enabled CGROUPS_CPUACCT: enabled CGROUPS_CPUSET: enabled CGROUPS_DEVICES: enabled CGROUPS_FREEZER: enabled CGROUPS_MEMORY: enabled error execution phase preflight: [preflight] Some fatal errors occurred: [ERROR FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables does not exist [ERROR Swap]: running with swap on is not supported. Please disable swap [ERROR SystemVerification]: failed to parse kernel config: unable to load kernel module: "configs", output: "", err: exit status 1 [preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...` To see the stack trace of this error execute with --v=5 or higher ++ Using your bootstrap script the kworker3 command below: sshpass -p "kubeadmin" scp -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no kmaster.lxd:/joincluster.sh /joincluster.sh 2>/tmp/joincluster.log bash /joincluster.sh >> /tmp/joincluster.log shows [root@kworker3 ~]# bash /joincluster.sh >> /tmp/joincluster.log W0315 05:30:20.165023 1873 join.go:346] [preflight] WARNING: JoinControlPane.controlPlane settings will be ignored when control-plane flag is not set. [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at kubernetes.io/docs/setup/cri/ [WARNING FileContent--proc-sys-net-bridge-bridge-nf-call-iptables]: /proc/sys/net/bridge/bridge-nf-call-iptables does not exist [WARNING Swap]: running with swap on is not supported. Please disable swap [WARNING SystemVerification]: failed to parse kernel config: unable to load kernel module: "configs", output: "", err: exit status 1 The only way to add a node successfully is by using the force ignore all error switch. Any idea what's going so I can understand better? This did not happen when provisioning the master and koworker1 nodes..:|

[@justmeandopensource]

Hi, thanks for watching. You can ignore those errors while adding the nodes. In fact in my bootstrap script I only whitelisted few error types. But things might have changed slightly. In my bootstrap script I usually ignore all errors. Cheers.

[@ankitvarshney5989]

hello, I setup the Kubernetes cluster using kops, then I want to rename the nodes. but after change the name of the node by using command kubectl edit node . after a minute, the changes were undone. I am really stuck. Please help.

[@justmeandopensource]

hi Ankit, I haven't tried that to be honest. Not sure if its possible. github.com/kubernetes/kops/issues/5767

[@cepi24]

which shell do you use? I mean it suggests shadow of command. Thx

[@justmeandopensource]

Hi, thanks for watching. I use gnome terminal in I3 window manager environment. I used zsh, oh-my-zsh and zsh-autosuggestion plugin for the shadow thing. Its basically showing commands from the history in the background. If you are interested, I have done videoa on my environment setup in the below playlist kzbin.info/aero/PL34sAs7_26wOgqJAHey16337dkqahonNX Thanks.

[@Aneez004]

Hi Venkat, I have a single node kubeadm cluster using ec2 instance running in one region. I am trying to take ami of the instance and deploy it in another region. But I am getting errors mostly due to nodenames and hostnames. Can you throw some light on how to tackle this situation?

[@justmeandopensource]

Hi Anees, thanks for watching. You can do kubeadm reset and kubeadm init again which will pick the right node name. This basically means, you are re-initializing the cluster. It is similar to setting up a new cluster.

[@Aneez004]

@@justmeandopensource Thanks for the reply. So if I use the same hostname (excluding region name), it may work without reset, right?

[@alfredo6083]

To change the name of the master node is the same operation? Thanks (delete + reset + create)

[@justmeandopensource]

Hi Alfredo, thanks for watching. This is not a recommended approach atleast not for the master. kubeadm reset will reset the entire cluster. The hostname decision has to be made before initializing the cluster.

[@alfredo6083]

@@justmeandopensource Thank you very much for your help!

[@justmeandopensource]

@@alfredo6083 you are welcome

[@RK-wk6zn]

can we rename a master node like this?

[@justmeandopensource]

Hi, one of the viewer tried to rename the node and Kubernetes components stopped working. So I tried and helped him by doing this video. Normally you wouldn't want to rename a node. I haven't tried renaming master node. I don't think it will work. Cheers.