ansible_fqdn different from ansible_hostname

[zakabluk]

ISSUE TYPE

• Bug Report

COMPONENT NAME

Generated facts with mistake.

ANSIBLE VERSION

ansible 2.4.2.0
python version = 2.7.5 (default, Aug 4 2017, 00:39:18) [GCC 4.8.5 20150623 (Red Hat 4.8.5-16)]

CONFIGURATION

default config

OS / ENVIRONMENT

CentOS Linux release 7.4.1708 (Core)

SUMMARY

I generated facts for server and have had result
Connecting to ecsc00a01c56.example.com [10.6.195.4] port 22.\

    "ansible_fqdn": "ecsc00100ea6.example.com",  - wrong name!
    "ansible_hostname": "ecsc00a01c56", 
     ansible_nodename": "ecsc00a01c56
      "ohai_fqdn": "ecsc00a01c56.example.com", 
    "ohai_hostname": "ecsc00a01c56", 

bash# hostname
ecsc00a01c56.example.com
server use CentOS Linux release 7.4.1708 (Core)

[ansibot]

Files identified in the description:

• lib/ansible/module_utils/facts

If these files are inaccurate, please update the component name section of the description or use the !component bot command.

click here for bot help

[sivel]

Ansible populates the value of ansible_fqdn using the socket.getfqdn() function.

getfqdn is documented as:

Get fully qualified domain name from name.

An empty argument is interpreted as meaning the local host.

First the hostname returned by gethostbyaddr() is checked, then
possibly existing aliases. In case no FQDN is available, hostname
from gethostname() is returned.

So the process that is followed is to use socket.gethostname which should return the locally configured hostname, then use that value to perform a DNS lookup of that configured hostname, and if any aliases are found, potentially from /etc/hosts that are aliases including an FQDN, that alias will be returned.

Here is an example:

>>> import socket
>>> socket.gethostname()
'vivo'
>>> socket.gethostbyaddr('vivo')
('vivo', ['foo.bar.baz'], ['127.0.1.1'])
>>> socket.getfqdn()
'foo.bar.baz'

Based on what we deem ansible_fqdn to be, this value is correct, but has the ability to be tainted by DNS or /etc/hosts records

If you have further questions please stop by IRC or the mailing list:

• IRC: #ansible on irc.freenode.net
• mailing list: https://groups.google.com/forum/#!forum/ansible-project

[zakabluk]

Hi! The problem was in wrong PTR record.