CODEWITHSUNDEEP
ansible
Amine Benatmane
Amine Benatmane

Reputation: 1261

Ansible merges group_vars when deploying to same host in different groups

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 ?

Upvotes: 8

Views: 4629

Answers (3)

dvanrensburg
dvanrensburg

Reputation: 1441

Even though it is a feature it becomes really annoying when you are using a local ansible connection to manage remote resources like databases.

I managed to get around this by using a unique name in the hosts in the hosts file.

The following playbook (print.yml) will print db1 and changing the hosts to group2 will print db2

---
- name: Manage DB
  hosts: group1
  tasks:
    - debug:
        msg: "{{ database.name }}"

Inventory folder:

dev
├── group_vars
│   ├── group1
│   │   └── all.yml
│   └── group2
│       └── all.yml
└── hosts
    └── all.yml

group_vars/group1/all.yml:

database:
  name: db1

group_vars/group2/all.yml:

database:
  name: db2

and contents of hosts/all.yml: (NOTE: the dbnode1 vs dbnode2 below)

all:
  children:
    group1: 
      hosts:
        dbnode1:
          ansible_connection: local
    group2: 
      hosts:
        dbnode2:
          ansible_connection: local

ansible -i dev print.yml

Upvotes: 0

mathmons
mathmons

Reputation: 121

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.

Upvotes: 12

Konstantin Suvorov
Konstantin Suvorov

Reputation: 68269

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.

Upvotes: 1

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