Ansible: How to get hostname without domain name?

Question

How to get value from /etc/hostname ignoring domain name. For example, /etc/hostname says "client.test.dom" and I need to get "client".

I have tried "{{ ansible_nodename | replace('.rail.dom','') }}" but I get syntax problem and can't figure out how to solve it.

Answer 1

It is assumed that you have a proper and valid inventory defined. Then, according Information about Ansible: magic variables

You can use the magic variable inventory_hostname, the name of the host as configured in your inventory, as an alternative to ansible_hostname when fact-gathering is disabled. If you have a long FQDN, you can use inventory_hostname_short, which contains the part up to the first period, without the rest of the domain.

If facts are gathered you can use additionally ansible_hostname or ansible_facts['nodename'].

A minimal example playbook

---
- hosts: localhost
  become: false
  gather_facts: true
tasks:

name: Show hostname
debug:
  msg: "Host: {{ ansible_hostname }} FQDN: {{ ansible_nodename }}"

will result into an output of

TASK [Show hostname] *********************
ok: [localhost] =>
  msg: 'Host: test FQDN: test.example.com'

---

You may then have a look into the following examples

  - name: Split nodename
    debug:
      msg: "{{ ansible_nodename.split('.')[0] }}"

name: Split nodename
debug:
  msg: "{{ ansible_nodename | split('.') | first }}"

resulting both into an output of

TASK [Split nodename] ******
ok: [localhost] =>
  msg: test

Further Documentation

• split filter – split a string into a list

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