everyone.
Please teach me why kubectl get nodes command does not return master node information in full-managed kubernetes cluster.
I have a kubernetes cluster in GKE. When I type kubectl get nodescommand, I get below information.
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
gke-istio-test-01-pool-01-030fc539-c6xd Ready <none> 3m13s v1.13.11-gke.14
gke-istio-test-01-pool-01-030fc539-d74k Ready <none> 3m18s v1.13.11-gke.14
gke-istio-test-01-pool-01-030fc539-j685 Ready <none> 3m18s v1.13.11-gke.14
$
Off course, I can get worker nodes information. This information is same with GKE web console. By the way, I have another kubernetes cluster which is constructed with three raspberry pi and kubeadm. When I type kubectl get nodes command to this cluster, I get below result.
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
master Ready master 262d v1.14.1
node01 Ready <none> 140d v1.14.1
node02 Ready <none> 140d v1.14.1
$
This result includes master node information.
I'm curious why I cannot get the master node information in full-managed kubernetes cluster. I understand that the advantage of a full-managed service is that we don't have to manage about the management layer. I want to know how to create a kubernetes cluster which the master node information is not displayed. I tried to create a cluster with "the hard way", but couldn't find any information that could be a hint.
At the least, I'm just learning English now. Please correct me if I'm wrong.
Because there are no nodes with that role. The control plane for GKE is hosted within their own magic system, not on your own nodes.
It's a good question!
The key is kubelet component of the Kubernetes.
Managed Kubernetes versions run Control Plane components on masters, but they don't run kubelet. You can easily achieve the same on your DIY cluster.
The kubelet is the primary “node agent” that runs on each node. It can register the node with the apiserver using one of: the hostname; a flag to override the hostname; or specific logic for a cloud provider.
https://kubernetes.io/docs/reference/command-line-tools-reference/kubelet/
When the kubelet flag --register-node is true (the default), the kubelet will attempt to register itself with the API server. This is the preferred pattern, used by most distros.
https://kubernetes.io/docs/concepts/architecture/nodes/#self-registration-of-nodes