CODEWITHSUNDEEP
ansible
lmills
lmills

Reputation: 11

Ansible - define settings based on host name prefix

I would like to be able to set values in an ansible playbook based on the prefix of a hostname.

e.g. hosts that start LondonXXXX receive the IP 192.168.1.1 for DNS hosts that start NewYorkXXX receive the IP 192.168.2.1 for DNS etc

I have tried various methods but don't seem to be able to get it to work. I am referencing the variables .yml in the playbook by:

  vars_files:
    - dns.yml

An example of a couple of things I have tried in the DNS.yml file:

---
- include:
  - name: Check if located in London
    set_fact: 
      DNS: '192.168.1.1'
    when: ansible_hostname.find("London") != -1

  - set_fact:
      DNS: '192.168.2.1'
    when: '"NewYork" in ansible_hostname'

I am new to using ansible so apologies if this is a simple syntax issue.

Upvotes: 1

Views: 3716

Answers (2)

Jack
Jack

Reputation: 6158

Seems to me it would be easier to have that variable in group_vars files. Your inventory would then put the London hosts into the London group, and the New York hosts into the New_York group.

Upvotes: 0

larsks
larsks

Reputation: 311238

A vars file is just a collection of name: value pairs. It can't have tasks. There also appear to be some syntax errors in the example you've posted, and possibly you're using some variables that don't actually exist.

If you want to use tasks like set_fact, that needs to go in a playbook. For example, you could do something like this:

- hosts: all
  gather_facts: false
  tasks:
    - name: Check if located in London
      set_fact:
        DNS: '192.168.1.1'
      when: >
        "London" in inventory_hostname

    - set_fact:
        DNS: '192.168.2.1'
      when: >
        "NewYork" in inventory_hostname

    - debug:
        msg: "Variable DNS is: {{DNS}}"

Given an inventory that looks like this:

London1234 ansible_host=localhost ansible_connection=local
NewYork1234 ansible_host=localhost ansible_connection=local

I can run the above playbook like this:

ansible-playbook playbook.yml -i hosts

And get:

PLAY [all] *********************************************************************************

TASK [Check if located in London] **********************************************************
ok: [London1234]
skipping: [NewYork1234]

TASK [set_fact] ****************************************************************************
skipping: [London1234]
ok: [NewYork1234]

TASK [debug] *******************************************************************************
ok: [London1234] => {
    "msg": "Variable DNS is: 192.168.1.1"
}
ok: [NewYork1234] => {
    "msg": "Variable DNS is: 192.168.2.1"
}

PLAY RECAP *********************************************************************************
London1234                 : ok=2    changed=0    unreachable=0    failed=0   
NewYork1234                : ok=2    changed=0    unreachable=0    failed=0

Upvotes: 1

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