CODEWITHSUNDEEP
configurationansible
Meeresgott
Meeresgott

Reputation: 461

Different variables values for every host in group in ansible

I have a role in ansible that expects different variables. I want to apply this role to a host group but every host in the group needs different values for this role.

I tried to archive this with this configuration: Group Var: 

host1: 
   var1: 'project a'
   var2: 'some other'

host2: 
   var1: 'project b'
   var2: 'some different'

hosts: 

[myHosts]
host1
host2

But I have no clue how can I loop to the different hosts in a play 

#something before

- hosts: myHosts
  become: true
  roles:
  - docker
  - docker-compose
  - git
  vars:
  - var1: ??
  # Something like this possible? 
  - var2: currentHost.var2

Or is my attempt wrong and I use the tool incorrect? This role is the last step for a deployment. So in the vars I want to say something like become project a or become project b. Would this be bad practice? Should I better have a role project a, project b and assign them to the specific host via playbook even if the only difference between the two roles are some env variables?

Upvotes: 3

Views: 3778

Answers (1)

Vladimir Botka
Vladimir Botka

Reputation: 68189

If you want to keep the data in group_vars put the variables into a dictionary. For example,

shell> cat group_vars/myhosts.yml
my_dict:
  host1: 
    var1: 'project a'
    var2: 'some other'
  host2: 
    var1: 'project b'
    var2: 'some different'

Then, the variables may be easily "assigned" to each host

- hosts: myhosts
  vars:
    var1: "{{ my_dict[inventory_hostname]['var1'] }}"
    var2: "{{ my_dict[inventory_hostname]['var2'] }}"

However, the best practice is to put such variables into the host_vars and let Ansible "assign" the variables to the hosts automatically. For example,

shell> cat host_vars/host1.yml
var1: 'project a'
var2: 'some other'

shell> cat host_vars/host2.yml
var1: 'project b'
var2: 'some different'

See Group And Host Variables.

Notes

  • To simplify the code and improve the readability, you can put the declarations of var* also into the group_vars. For example,
shell> cat group_vars/myhosts.yml
my_dict:
  host1: 
    var1: 'project a'
    var2: 'some other'
  host2: 
    var1: 'project b'
    var2: 'some different'

var1: "{{ my_dict[inventory_hostname]['var1'] }}"
var2: "{{ my_dict[inventory_hostname]['var2'] }}"

Upvotes: 3

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