run_once in a role combined with when in a playbook is erratic

[nneubauer]

Issue Type: Bug Report

Ansible Version: 1.9.3

Ansible Configuration: Nothing special

Environment: Mac OS X 10.11

Summary:

A playbook that does apply a role under certain circumstances (using when) is created. Within the role a task is tagged with run_once. Now, it seems that run_once just selects the first host that was matched from the playbook. If that host however actually fails the when validation from the roles definition. The task is never run (skipped).

  roles:
  - {
    role: some-role,
    when: "'some_group' in group_names",
    sudo: yes,
    }

- name: Some Task
  template: src=some-file.j2 dest=/opt/some-file
  run_once: true

Steps To Reproduce:

Basically look at the above example. Make sure your hosts: definition matches at least two hosts and your when definition matches only a subset.

Expected Results:

I expect the task in the playbook to run_once on one of the hosts that actually are covered by the when statement from the playbook.

Actual Results:

Sometimes (depending on the order of your matched hosts), the task is not run at all but marked as skipped for one host that when does not match on.

[sivel]

run_once will run on the first host in the list of hosts in the play. Using a when statement that potentially limits based on host facts or groups could be expected to result in this behavior.

To ensure that it runs on a valid host, you could use 'delegate_to`

[nneubauer]

Well, I get "what it does" to achieve what it promises, but for me it seems that the solution is not working. From a role's point of view I can not know from what kind of playbook I am run. I can certainly not use delegate_to because in my case I have no knowledge about the inventory. I had to solve it by adding a mandatory variable for the role containing the inventory_hostname that the specific run_once task should be run on.

[bcoca]

what you are asking is for a 'run_once_successfully' which is not a current feature.

[ansibot]

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[kmadnani]

this issue affects me too.

[alexhexabeam]

For anyone finding this from google, here's one that's still open for this ticket. #23594

[stevanikof]

I solve this by putting the 'when' before the 'run_once'
This narrows the host list to a set I want to run once on

[Timoses]

I solve this by putting the 'when' before the 'run_once'
This narrows the host list to a set I want to run once on

This does not work.
Plus, I doubt that the order of keywords matters (it should not!)!