Why KubeADM need DNS resolver by modifying /etc/hosts file in each node on K8S Cluster ?

[haminhcong]

In following blogs + articles:

• https://awesomeopensource.com/project/cookeem/kubeadm-ha
• https://stackoverflow.com/questions/45391667/kubeadm-v1-7-2-hostname-could-not-be-reached

Author always recommend update /etc/hosts file. If we don't want to modify /etc/hosts manualy, we must have dns resolver to resolve hostname of each node in our k8s cluster, or using option

kubelet-preferred-address-types: InternalIP

• https://www.linode.com/community/questions/19756/how-can-i-deploy-the-kubernetes-metrics-server-on-lke
• https://gitlab.datahub.erdc.ericsson.net/syafiq/assignment_3-4/tree/master/metrics-server
• https://kubernetes.io/docs/reference/command-line-tools-reference/kube-apiserver/

[haminhcong]

Need an experiment test using kubeadm to setup k8s cluster, on non DNS enviroment to verify this problem