modify /etc/hosts file hostname from inventory file

ansible_modify_hostname.yaml

REF: https://gist.github.com/phips/11233502

  - name: Ensure hostname set from inventory file
    tags: etchostsupdate
    hostname: name={{ inventory_hostname }}
    when: not inventory_hostname|match('(\d{1,3}\.){3}\d{1,3}')

  - name: Update the /etc/hosts file with node name
    tags: etchostsupdate
    become: yes
    become_user: root
    lineinfile:
      path: "/etc/hosts"
      regexp: "{{ hostvars[item]['ansible_env'].SSH_CONNECTION.split(' ')[2] }}\t{{ hostvars[item]['ansible_fqdn']}}\t{{ hostvars[item]['ansible_hostname']}}"
      line: "{{ hostvars[item]['ansible_env'].SSH_CONNECTION.split(' ')[2] }}\t{{ hostvars[item]['ansible_fqdn']}}\t{{ hostvars[item]['ansible_hostname']}}"
      state: present
      backup: yes
    register: etchostsupdate
    when: ansible_hostname != "{{ item }}" or ansible_hostname == "{{ item }}"
    with_items: "{{ansible_play_hosts}}"

ansible playbook inventory file

[test-hadoop-cluster]
hadoop-m1.example.com ansible_user=user ansible_host=172.16.193.16
hadoop-n1.example.com ansible_user=user ansible_host=172.16.193.181
hadoop-n2.example.com ansible_user=user ansible_host=172.16.193.40