Ansible hostname and timezone Modules

Introduction

System identity and time configuration are foundational server setup tasks. Ansible's hostname and timezone modules configure these idempotently, ensuring consistency across your fleet.

Set Hostname

# Set the system hostname
- name: Set hostname
  ansible.builtin.hostname:
    name: "{{ inventory_hostname }}"

# Set FQDN
- name: Set hostname
  ansible.builtin.hostname:
    name: web-01.prod.example.com

# Update /etc/hosts to match
- name: Update /etc/hosts
  ansible.builtin.lineinfile:
    path: /etc/hosts
    regexp: '^127\.0\.1\.1'
    line: "127.0.1.1 {{ inventory_hostname }}.{{ domain }} {{ inventory_hostname }}"

Hostname Parameters

Parameter	Description
`name`	Hostname to set (required)
`use`	Backend: `systemd`, `debian`, `redhat`, `alpine`, etc. (auto-detected)

Set Timezone

# Set timezone
- name: Set timezone to UTC
  community.general.timezone:
    name: UTC

# Set to specific timezone
- name: Set timezone
  community.general.timezone:
    name: America/New_York

# Set European timezone
- name: Set timezone
  community.general.timezone:
    name: Europe/Rome

Common Timezones

Timezone	Region
`UTC`	Universal
`America/New_York`	US Eastern
`America/Chicago`	US Central
`America/Denver`	US Mountain
`America/Los_Angeles`	US Pacific
`Europe/London`	UK
`Europe/Berlin`	Germany
`Europe/Rome`	Italy
`Europe/Paris`	France
`Asia/Tokyo`	Japan
`Asia/Shanghai`	China
`Asia/Kolkata`	India
`Australia/Sydney`	Australia Eastern

# List all available timezones
timedatectl list-timezones

Configure NTP

# Install and configure chrony (modern NTP)
- name: Install chrony
  ansible.builtin.package:
    name: chrony
    state: present

- name: Configure NTP servers
  ansible.builtin.template:
    src: chrony.conf.j2
    dest: /etc/chrony/chrony.conf
  notify: Restart chrony

- name: Enable chrony
  ansible.builtin.service:
    name: chronyd
    state: started
    enabled: true

# Or use systemd-timesyncd
- name: Enable NTP with timedatectl
  ansible.builtin.command: timedatectl set-ntp true
  changed_when: false

Practical Pattern: Full System Bootstrap

---
- name: Bootstrap server identity
  hosts: all
  become: true
  tasks:
    - name: Set hostname
      ansible.builtin.hostname:
        name: "{{ inventory_hostname }}"

    - name: Configure /etc/hosts
      ansible.builtin.blockinfile:
        path: /etc/hosts
        marker: "# {mark} ANSIBLE MANAGED"
        block: |
          127.0.0.1 localhost
          127.0.1.1 {{ inventory_hostname }}.{{ domain }} {{ inventory_hostname }}
          {% for host in groups['all'] %}
          {{ hostvars[host]['ansible_host'] }} {{ host }}.{{ domain }} {{ host }}
          {% endfor %}

    - name: Set timezone
      community.general.timezone:
        name: "{{ server_timezone | default('UTC') }}"

    - name: Install NTP
      ansible.builtin.package:
        name: chrony
        state: present

    - name: Enable NTP
      ansible.builtin.service:
        name: "{{ 'chronyd' if ansible_os_family == 'RedHat' else 'chrony' }}"
        state: started
        enabled: true

    - name: Set locale
      ansible.builtin.command: localectl set-locale LANG=en_US.UTF-8
      changed_when: false

Set Locale

# Generate locale
- name: Generate locale
  community.general.locale_gen:
    name: en_US.UTF-8
    state: present

# Set system locale
- name: Set default locale
  ansible.builtin.command: localectl set-locale LANG=en_US.UTF-8
  changed_when: false

# Or with file
- name: Set locale via file
  ansible.builtin.copy:
    content: |
      LANG=en_US.UTF-8
      LC_ALL=en_US.UTF-8
    dest: /etc/default/locale

Troubleshooting

Hostname Reverts After Reboot

Ensure cloud-init isn't overriding it:

# Disable cloud-init hostname management
- name: Prevent cloud-init from changing hostname
  ansible.builtin.copy:
    content: "preserve_hostname: true\n"
    dest: /etc/cloud/cloud.cfg.d/99-hostname.cfg
  when: ansible_service_mgr == 'systemd'

Timezone Module Not Found

Install the collection:

ansible-galaxy collection install community.general

Conclusion

ansible.builtin.hostname and community.general.timezone handle fundamental server identity. Set hostname from inventory_hostname for consistency. Always update /etc/hosts to match. Use UTC for servers unless there's a specific reason not to. Configure NTP (chrony) for accurate time — critical for logging, certificates, and cluster coordination. These should be the first tasks in any server bootstrap playbook.