Using facts from one host group to configure another host group with Ansible

Question

I am trying to configure one set of hosts [nodes] using facts from another set of hosts [etcd]. Here is my hosts file

[master]
kubernetes ansible_ssh_host=10.2.23.108

[nodes]
n1 ansible_ssh_host=10.2.23.192
n2 ansible_ssh_host=10.2.23.47

[etcd]
etcd01 ansible_ssh_host=10.2.23.11
etcd02 ansible_ssh_host=10.2.23.10
etcd03 ansible_ssh_host=10.2.23.9

Note that the group [etcd] is not the target of provisioning - [nodes] is. But provisioning [nodes] requires knowledge of the facts of [etcd].

Here is my playbook:

---
- name: Configure common
  hosts: nodes
  sudo: True
  tasks:
    - name: etcd endpoints
      file: dest=/etc/kubernetes state=directory

    - name: etcd endpoints
      template: src=files/k.j2 dest=/etc/kubernetes/apiserver

Finally, here is the template for files/k.j2

KUBE_ETCD_SERVERS="--etcd_servers="{% for host in groups['etcd'] %}https://{{hostvars[host]['ansible_eth0']["ipv4"]["address"]}}:2380{% if not loop.last %},{% endif %}{% endfor %}"

The goal is to produce a KUBE_ETCD_SERVERS value that looks like

--etcd_servers=https://10.2.23.11:2380,https://10.2.23.10:2380,https://10.2.23.10:2380

When I run this playbook I get console output

TASK [etcd endpoints] **********************************************************
fatal: [n1]: FAILED! => {"changed": false, "failed": true, "msg": "AnsibleUndefinedVariable: 'dict object' has no attribute 'ansible_eth0'"}
fatal: [n2]: FAILED! => {"changed": false, "failed": true, "msg": "AnsibleUndefinedVariable: 'dict object' has no attribute 'ansible_eth0'"}

What is the idiomatic Ansible way to make the etcd facts available to the node play?

can you run the setup module against one of the server and paste the output. May be it doesn't have ansible_eth0 — Arbab Nazar
Possible there's no eth0 on etcd. Or, once time i've become same error when changing iptables to firewalld (some depended packages were removed as 'unused') — A K
Thanks. Here is the setup module run against an etcd server: gist.github.com/ae6rt/44f2567e287dd502e714b811bcd0ba92. eth0 does in fact exist. — ae6rt
I should have included my Ansible version: $ ansible --version ansible 2.1.1.0 config file = /Users/mpetrovic/Projects/ae6rt/ansible-other-hosts/ansible.cfg configured module search path = Default w/o overrides — ae6rt

Konstantin Suvorov Konstantin Suvorov · Accepted Answer · 2016-08-24T17:56:06

If you want to use facts of some host, you should gather them first.
Run setup task on [etcd] hosts to populate hostvars.

---
- name: Gather etcd facts
  hosts: etcd
  tasks:
    - setup:

- name: Configure common
  hosts: nodes
  sudo: True
  tasks:
    - name: etcd endpoints
      file: dest=/etc/kubernetes state=directory

    - name: etcd endpoints
      template: src=files/k.j2 dest=/etc/kubernetes/apiserver

Using facts from one host group to configure another host group with Ansible

1 Answers