Ubuntu – ansible: setting variable according to ansible_os_family

ansibleredhatUbuntu

Using ansible 2.0.2.0, I want to deploy a file to destination server. The destination folder is different on Debian and RedHat family.

I have used set_fact, but it seems that it used the last defined, ignoring the when: option.

I don't want to use variable files, because this variable is only used in this particular playbook

Duplicating the copy task into RedHat and Debian, while possible, will complicate maintenance in the future.

The playbook below will fail when executed against Ubuntu server because destination was expanded to become /etc/nrpe.d which is for RedHat

- set_fact:
  destination: "/etc/nagios/nrpe.d/"
  when: ansible_os_family == "Debian"

- set_fact:
  destination: "/etc/nrpe.d/"
  when: ansible_os_family == "RedHat"

- name: Ensure Nagios custom checks directory exists
  file: path=/usr/local/lib/nagios/plugins state=directory mode=0755

- name: Install check_cpu_steal
  copy: src=eprepo/sysadmin/nagios_checks/check_cpu_steal dest=/usr/local/lib/nagios/plugins/check_cpu_steal mode=0755 owner=root group=root

- name: Install check_cpu_steal command to /etc/nrpe.d
  copy: src=eprepo/sysadmin/files/check_cpu_steal.conf dest="{{ destination }}/check_cpu_steal.conf mode=0644 owner=root group=root"

Best Answer

I have solved my own problem.

In essence, you can set variable according to os_family, but you have to do it correctly.

See my fixed playbook below:

---
- name: Set fact for Debian
  set_fact:
    destination: "/etc/nagios/nrpe.d/"
    nrpe_server: "nagios-nrpe-server"
  when: ansible_os_family == "Debian"

- name: Set fact for RedHat
  set_fact:
    destination: "/etc/nrpe.d/"
    nrpe_server: "nrpe"
  when: ansible_os_family == "RedHat"

- name: Ensure Nagios custom checks directory exists
  file: path=/usr/local/lib/nagios/plugins state=directory mode=0755

- name: Install check_cpu_steal nagios check
  copy: src=eprepo/sysadmin/nagios_checks/check_cpu_steal dest=/usr/local/lib/nagios/plugins/check_cpu_steal mode=0755 owner=root group=root

- name: Install check_cpu_steal nrpe config
  copy: src=eprepo/sysadmin/files/check_cpu_steal.conf dest="{{ destination }}/check_cpu_steal.cfg" mode=0644 owner=root group=root

- name: Restart nrpe daemon
  service: name={{ nrpe_server }} state=restarted

Related Solutions

How to see stdout of ansible commands

I think you can register the result to a variable, then print with debug.

- name: print to stdout
  command: echo "hello"
  register: hello

- debug: msg="{{ hello.stdout }}"

- debug: msg="{{ hello.stderr }}"

Ansible Host Variables – How to Access Host Variable of a Different Host with Ansible

You can access pretty much any inventory facts/variables by doing something like this:

{{ hostvars['foo.example.com']['ansible_eth0']['ipv4']['address'] }}

or, if you want to do it via an index into a group:

{{ hostvars[groups['collectors'][0]]['ansible_eth0']['ipv4']['address'] }}

The big trick is that you need to collect the facts for all the hosts/groups you're interested in. So you would want to modify your playbook that runs against the reporters group to include a no-op (dummy) task that is applied to the collectors group. That will cause Ansible to collect facts about the collectors hosts so that they can be accessed from the reporters group. So you might want to add something like this to the top of your reporters playbook:

- hosts: collectors
  name: Gather facts from collectors
  tasks: [ ]

The empty brackets basically mean that no tasks will be executed, but this will still force Ansible to gather facts about the collectors so that you can then reference them in the tasks that you run against your reporters.

Edit #1

It occurred to me that I should also mention that as of version 1.8 of Ansible, there is a fact-caching feature that is now available. Fact caching relies on a redis server to store facts between playbook runs. With it enabled, one playbook can reference facts that were obtained by another playbook that was run previously. The example the Ansible documentation gives:

Imagine, for instance, a very large infrastructure with thousands of hosts. Fact caching could be configured to run nightly, but configuration of a small set of servers could run ad-hoc or periodically throughout the day. With fact-caching enabled, it would not be necessary to “hit” all servers to reference variables and information about them.

Best Answer

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How to see stdout of ansible commands

Ansible Host Variables – How to Access Host Variable of a Different Host with Ansible

Edit #1

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