Ansible merges group_vars when deploying to same host in different groups

Question

Here's an example of the problem:

inventory file:

[group1] www.example1.com

[group2] www.example1.com

group_vars files:

group_vars/group1:
    a_var: aaa

group_vars/group2:
    a_var: bbb

If we run this playbook:

- name: ...
  hosts: group1
  roles:
    - ...

The variables from group_vars/group1 and group_vars/group2 overwrite each other if we're deploying to the same server.

Expected result: a_var=aaa

Actual result: a_vars=bbb

It seems like the vars get parsed and attached to the host rather than the staying with the group (so group_vars get merged even if you are not using that group and last group merged wins !!!!). is that a normal behavior ?

Answer 1

As a workaround, you can choose a different name for each group and set the var ansible_host for each with true hostname/IP. Example:

[group1]
example1-group1 ansible_host=192.168.0.10

[group2]
example1-group2 ansible_host=192.168.0.10

In this case, Ansible considers that you have two different hosts, with dedicated hostvars and groupvars but reaches them the same way.

Answer 2

is that a normal behavior ?

Yes, if host is in multiple groups, variables from only one group (the latter) will be honored.

From docs:

It is ok to put systems in more than one group, for instance a server could be both a webserver and a dbserver. If you do, note that variables will come from all of the groups they are a member of, and variable precedence is detailed in a later chapter.