The value for `mon_initial_members` in `ceph.conf` should not be a FQDN

[ykazakov]

According to Ceph documentation the value of mon_initial_members should be short host names, not FQDN.

However, currently the template ceph.conf.j2 sets this value to names which is initialized from the ansible inventory vars['ansible_play_hosts'], which, in principle, could be FQDN.

This results in Ceph monitors not to be properly configured.

I think the value {{ host }} here should be replaced with {{ hostvars[host]['ansible_facts']['hostname'] }}.

[tokred]

Related, as the play activates Messenger v2 protocol, the value of mon_host could/should be reformatted too: As only default ports are used by the play, there is not even the need for the lengthy v1/v2 syntax but a mere list of IP adresses would suffice.