How to persist variables/facts in ansible?

[Diwaakartg Ganesh]

checking out the documentation, modules like set_fact and register have scope only for that specific host. There are many purpose of using the variables from one host to another.

Alternatives I can think of:

1. using Command module and echoing the variables to a file. Later, using the variable file using vars section or include.

2. Setting the env variables and then accessing it but this will be difficult.

So what is the solution?

[Takeshi Yaegashi]

Hello,

You can use hostvars[hostname] to get facts set by other hosts.  play_hosts array is also useful. 

The following playbook collects root's SSH public keys from all hosts, then distributes keys back to all hosts.

---
- hosts: all
  sudo: yes
  gather_facts: no
  vars:
    pubkeys: |
      {%- for i in play_hosts %}
      {%-   set k = hostvars[i].pubkey %}
      {%-   if k %}
      {{      k }}
      {%    endif %}
      {%- endfor %}
  tasks:
    - command: cat /root/.ssh/id_rsa.pub
      register: r
      failed_when: false
    - set_fact:
        pubkey: "{{ r.stdout | default('') }}"
    - debug:
        var: pubkeys
    - authorized_key:
        user: root
        key: "{{ pubkeys }}"

Possible improvement: it would be nice if this playbook could also distribute all host keys into /root/.ssh/known_hosts of each host.

Regards,

-- 

YAEGASHI Takeshi <yaeg...@debian.org>