Debugging

This folder contains some Ansible playbooks to use to compare the ansible-playbook behavior to the ansible-inventory behavior, which is expected to be identical.

Surprising empty groups behavior

The following files will define a group that is empty:

• scripts/var_files/just_host.py
• scripts/empty_group.py

These should be used as the inventory file for running the example add_host_and_echo.yml as follows.

ansible-playbook -i {inventory file} debugging/add_host_and_echo.yml

The surprising outcome is that the second set of print statements detect the group vars (inside hostvars), whereas the first print statements before the addition of the new host contains no trace of the group.

Even more surprising is the fact that the empty_group.py shows the empty group (barfoo) in the group list before the host add, whereas the second one does not.

The behavior here has several issues

• Ansible should show groups that come from variable plugins when the variable groups is referenced
• ansible-inventory should show the variables on groups

The first issue can be replicated simply by comparing the output of the following two commands.

ansible-inventory -i scripts/empty_group.py --list
ansible-inventory -i scripts/var_files/just_host.py --list

The first command shows the empty group, but the second command does not.

Why this is a problem:

credit to reference:

https://github.com/chrismeyersfsu/test-awx-job/commit/a32753bff0ca600bc886157f1fe53a98f3afc699

The point of ansible-inventory is to produce the same behavior as ansible-playbook. This is violated in cases where add_host is used when the inventory contains empty groups created by vars plugins.

An established example of this is the following.

ansible-inventory -i scripts/var_files/just_host.py --list --yaml > saved.yaml
# Test case A
ansible-playbook -i saved.yaml debugging/add_host_and_echo.yml 
# Test case B
ansible-playbook -i scripts/var_files/just_host.py debugging/add_host_and_echo.yml 

Here, the original source inventory is ./inventory/partial. However, we can see that the representation that ansible-inventory creates of this inventory is incomplete. This leads to test case A yielding different results from test case B.