Pass Ansible variables from one role (running on one host) to another role running on another host within the same playbook

Question

I have a playbook that runs different roles on different hosts. Is it possible to pass a variable from one role running on one host to another role on another host running within the same playbook run? Or any workaround ?

playbook
   host1
     role1
       here I get some variables: var1 var2 ...etc
   host2
     role2
       here I need to use var1 var2 ... etc from the above host/role

The task in role1 that sets teh variable db looks like this:

- shell: cd /ACE/conf && grep ^db.url local1.properties | awk -F/ '{print $4}' | awk -F? '{print $1}'
  register: db

UPDATE: On the first host the values are dynamic, it's like a configuration file that is always updated. After I store the values in variables on host1 with the role1 I then move to the host2, run the role2 and do stuff with those values from variables stored by host1.

I tried with hostvars:

{{ hostvars.LBL.db.stdout }}
{{ hostvars['LBL']['db'] }}
{{ hostvars['LBL']['db']['stdout'] }}

and I get error:

in get_variables raise Exception("host not found: %s" % hostname) Exception: host not found: LBL

LBL exists in hosts as on it I run the first role

I set a variable on one host and I want that variable to be available to the other host. All this within a single playbook. Can it be done ?

hostvars is not working using it like this:

---   
- name: test hostvars host1
  hosts: LBL
  tasks:
    - command: "ls /bin"
        register: ls_out

- name: test hostvars host2
  hosts: LM
  tasks:
    - debug:
        var: "{{ hostvars['LBL']['ls_out']['stdout'] }}"

error:

fatal: [10.104.148.138] => host not found: LBL

/etc/ansible/hosts

[root@NS1 ansible]# cat /etc/ansible/hosts
[LBL]
10.104.148.136
[LM]
10.104.148.138

Answer 1

The problem is in your inventory.

This message:

fatal: [10.104.148.138] => host not found: LBL

is because LBL is a group and not a host. Group LBL has one host in it: 10.104.148.136

Do one of the following:

1. Change your inventory (/etc/ansible/hosts) to:

LBL ansible_ssh_host=10.104.148.136
LM ansible_ssh_host=10.104.148.138

2. or if you really know what you're doing and LBL is a group and you wanna keep it that way then access the variable with:

{{ hostvars['10.104.148.136']['db']['stdout'] }}

Again LBL is a group not a host. More info.

Answer 2

This topic is complicated, and there are two different answers depending on what you want.

Access a variable defined in one role inside other for the same host

Example:

---
- hosts: host1
- roles:
    - role1
    - role2

Goal: You want to access some variable from role1 inside role2.

Use set_fact module.

Inside role1:

name: save precious value
set_fact: 
  pantsu: shiroi

Inside role2:

name: Nozoki...
debug: msg="Color is {{ pantsu }}"

Access to static variable for one host (or group) to other

Example:

[group_foo]
host1
host2
[group_bar]
host3
host4

group_vars/group_foo

important_value=bla-bla-ba

Goal: You want to use it in playbook for group2.

This is much trickier to do.

Inside group_vars/group_bar

other_var: '{{hostvars[groups["group_foo"][0]].important_value}}'

You can use other indexes besides '0'.

Answer 3

Here's my solution. My task was to sync data between two servers and I wanted to pass in the server names like this: ansible-playbook sync.yaml -e "source=host1 destination=host2"

Here's the main playbook:

---

- name: get_sync_facts
  hosts: "{{ source }}"
  roles:
    - set_sync_facts

- name: sync
  hosts: "{{ destination }}" 
  roles:
    - get_sync_facts
    - sync

Here's the set_sync_facts role:

---

- set_fact: src_media_dir='/some/dir/'
- set_fact: src_user='myuser'
- set_fact: src_host='1.1.1.1'
- set_fact: src_port=12345
- set_fact: src_db_user='dbuser'
- set_fact: src_db_password='something'
- set_fact: src_db_name='some_db'

(I actually derived some of these from tasks and others from host vars but you get the point)

And here's the get_sync_facts role:

---

- set_fact: src_media_dir={{ hostvars[source]['src_media_dir'] }}
- set_fact: src_user={{ hostvars[source]['src_user'] }}
- set_fact: src_host={{ hostvars[source]['src_host'] }}
- set_fact: src_port={{ hostvars[source]['src_port'] }}
- set_fact: src_db_user={{ hostvars[source]['src_db_user'] }}
- set_fact: src_db_password={{ hostvars[source]['src_db_password'] }}
- set_fact: src_db_name={{ hostvars[source]['src_db_name'] }}

You could do without this and just reference hostvars directly in your plays but this seemed easier to maintain as it corresponds directly with the set_sync_facts role.

Answer 4

it is quite old topic, but maybe it will be helpfull to somebody. I used sed to get hostname based on "target" specified in extra parameters.

To use this "target" group must contain only 1 hostname.

My inventory hosts:

[ansible_local]
localhost

[machine1]
machine1.domain.tld

upgrade_packages.yml

---
- hosts: '{{ target }}'
  sudo: yes
  tasks:
  - name: check for Debian system
    shell: /bin/false
    when: ansible_pkg_mgr != "apt"

  - name: full-upgrade all packages
    apt: update_cache=yes upgrade=full
    register: upgrade_result

- hosts: ansible_local
  tasks:
  - name: find out host from target
    shell: /bin/sed -n -e '/^\[{{ target }}\]$/,/^\[.*\]$/ { /^\[/d; /^$/d; p; }' {{ inventory_file }}
    register: target_inventory

  - name: Display all facts from target machine (change when to true if needed)
    debug: var=hostvars[target_inventory.stdout]
    when: false

  - name: Display upgrade result on ansible_local node
    debug: var=hostvars[target_inventory.stdout].upgrade_result.msg

Invoke with: ansible-playbook ./upgrade-packages.yml -e "target=machine1" -v

Answer 5

I had a similar setup where there are three hosts h1,h2,h3 and on each of them I wanted to define a fact { "important_fact": "foo" } (and bar, and baz, respectively)

To obtain a list containing all the different important_facts on all hosts, you can do this like so:

- set_fact:
    important_facts_list: "{{ hostvars | json('*.important_fact') }}"
  run_once: yes
  delegate_to: h1

important_facts_list will contain [ 'foo', 'bar', 'baz' ], and you can now iterate over them using with_items.