Autopilot: Nagios uses the wrong subnet IP to reach one host

After deploying Openstack with Landscape Autopilot, one of the hosts always fails all the checks in Nagios with a "CHECK_NRPE: Error - Could not complete SSL handshake" error. This error always happens in all Autopilot deployments and always for the same node.

The issue is caused by Nagios having the wrong IP address for that host in /etc/nagios3/conf.d/charm.cfg

The host entry in /etc/nagios3/conf.d/charm.cfg points to the private IP instead of the public IP:

define host {
  use generic-host
  statusmap_image base/ubuntu.gd2
  icon_image_alt Ubuntu Linux
  vrml_image ubuntu.png
  host_name <REMOVED - hostname of the host that fails>
  icon_image base/ubuntu.png
 address <REMOVED - private IP of the host>
}

Here is another entry from a similar host that works fine in Nagios:

define host {
  use generic-host
  statusmap_image base/ubuntu.gd2
  icon_image_alt Ubuntu Linux
  vrml_image ubuntu.png
  host_name <REMOVED - hostname of a host that works>
  icon_image base/ubuntu.png
 address <REMOVED - FQDN of the host in the form hostname.maas>
}

hostname.maas points to the public IP of the host instead of the private IP.

The workaround is to modify the address line of the bad host entry to be <hostname>.maas which points to the public IP and to restart Nagios.

We suspect that MAAS or Juju is not doing the right thing somewhere which leads to an incorrect entry in /etc/nagios3/conf.d/charm.cfg file.