cluster.cfg
<?xml version="1.0"?>
<cluster name="xxxx-CLUSTER" config_version="6">

  <cman transport="udpu" keyfile="/var/lib/pve-cluster/corosync.authkey">
  </cman>

  <clusternodes>
  <clusternode name="server1" votes="1" nodeid="1"/>
  <clusternode name="kebab" votes="1" nodeid="2"/></clusternodes>

</cluster>

/etc/hosts
127.0.0.1       localhost.localdomain localhost
37.xxx.xxx.xxx    server1.xxx.xxx        server1
151.xxx.xxx.xxx   kebab.xxx.xxx         kebab
::1     ip6-localhost ip6-loopback
feo0::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts