Testing delegation to localhost

ansible-delegate.yml

# vim: noai:ts=2:sw=2:et
---

- name: "testing hosts and delgation"

# ansible-playbook --connection=local -i "localhost,ubuntu"  a.yml

  hosts: all
  gather_facts: no

  tasks:

    - name: "always run"
      debug:  msg="inventory_hostname is {{inventory_hostname}}"

    - name: "only run this task when on localhost"
      debug: msg="we are localhost"
      when: "{{ inventory_hostname == 'localhost' }}"

    - name: "delegate to 127.0.0.1 if localhost or no delegate" 
      command: hostname 
      delegate_to: "{{ '127.0.0.1' if inventory_hostname == 'localhost' else omit }}"
      register: cmd
    - debug: var=cmd.stdout

    - name: "delegate to 127.0.0.1 if ubuntu or no delegate" 
      command: hostname 
      delegate_to: "{{ '127.0.0.1' if inventory_hostname == 'ubuntu' else omit }}"
      register: cmd
    - debug: var=cmd.stdout

output

nick@nick-Lenovo-Z710:~/workspace/openstack/k5-infra2$ ansible-playbook --connection=local -i "localhost,ubuntu"  a.yml 

PLAY [testing hosts and delgation] *********************************************

TASK [always run] **************************************************************
ok: [localhost] => {
    "msg": "inventory_hostname is localhost"
}
ok: [ubuntu] => {
    "msg": "inventory_hostname is ubuntu"
}

TASK [only run this task when on localhost] ************************************
ok: [localhost] => {
    "msg": "we are localhost"
}
skipping: [ubuntu]

TASK [delegate to 127.0.0.1 if localhost or no delegate] ***********************
changed: [localhost -> 127.0.0.1]
changed: [ubuntu]

TASK [debug] *******************************************************************
ok: [localhost] => {
    "cmd.stdout": "nick-Lenovo-Z710"
}
ok: [ubuntu] => {
    "cmd.stdout": "TX200-S5"
}

TASK [delegate to 127.0.0.1 if ubuntu or no delegate] **************************
changed: [ubuntu -> 127.0.0.1]
changed: [localhost]

TASK [debug] *******************************************************************
ok: [localhost] => {
    "cmd.stdout": "nick-Lenovo-Z710"
}
ok: [ubuntu] => {
    "cmd.stdout": "nick-Lenovo-Z710"
}

PLAY RECAP *********************************************************************
localhost                  : ok=6    changed=2    unreachable=0    failed=0   
ubuntu                     : ok=5    changed=2    unreachable=0    failed=0   

delegate to 127.0.0.1 if localhost or no delegate ----------------------- 0.33s
delegate to 127.0.0.1 if ubuntu or no delegate -------------------------- 0.14s
only run this task when on localhost ------------------------------------ 0.04s
always run -------------------------------------------------------------- 0.03s
 ------------------------------------------------------------------------ 0.03s

Playbook finished: Sat Jan 28 12:25:54 2017, 5 total tasks.  0:00:00 elapsed. 

cool stuff, thanks