Changing the hostname of a MetalK8s node¶

On the node, change the hostname:

$ hostnamectl set-hostname <New hostname>
$ systemctl restart systemd-hostnamed

Check that the change is taken into account.

$ hostnamectl status

Static hostname: <New hostname>
Pretty hostname: <New hostname>
  Icon name: computer-vm
   Chassis: vm
Machine ID: 5003025f93c1a84914ea5ae66519c100
   Boot ID: f28d5c64f06c48a3a775e24c4f03d00c
   Virtualization: kvm
Oerating System: CentOS Linux 7 (Core)
   CPE OS Name: cpe:/o:centos:centos:7
       Kernel: Linux 3.10.0-957.12.2.el7.x86_64
   Architecture: x86-64

On the bootstrap node, check the hostname edition incurred a change of status on the bootstrap. The edited node must be in a NotReady status.
```
$ kubectl get <node_name>
<node_name>    NotReady   etcd,master                   19h       v1.11.7
```

Change the name of the node in the yaml file used to create it. Refer to Creating a Manifest for more information.

apiVersion: v1
kind: Node
metadata:
  name: <New_node_name>
  annotations:
    metalk8s.scality.com/ssh-key-path: /etc/metalk8s/pki/salt-bootstrap
    metalk8s.scality.com/ssh-host: <node control-plane IP>
    metalk8s.scality.com/ssh-sudo: 'false'
  labels:
    metalk8s.scality.com/version: '127.0.4-dev'
    <role labels>
spec:
  taints: <taints>

Then apply the configuration:

$ kubectl apply -f <path to edited manifest>

Delete the old node (here <node_name>):
```
$ kubectl delete node <node_name>
```

Open a terminal into the Salt Master container:

$ kubectl -it exec salt-master-<bootstrap_node_name> -n kube-system -c salt-master bash

Delete the now obsolete Salt Minion key for the changed Node:
```
$ salt-key -d <node_name>
```

Re-run the deployment for the edited Node:

$ salt-run state.orchestrate metalk8s.orchestrate.deploy_node   saltenv=metalk8s-127.0.4-dev   pillar='{"orchestrate": {"node_name": "<new-node-name>"}}'


     Summary for bootstrap_master
     -------------
     Succeeded: 11 (changed=9)
     Failed:     0
     -------------
     Total states run:     11
     Total run time:  132.435 s

On the edited node, restart the Kubelet service:
```
$ systemctl restart kubelet
```