Playbook 1

when we first connect to a remote host/s, the remote host will already have some python version installed - the auto-discovery feature will find it
now we install ansible-docker on the remote host
from this time on: the ansible-docker docs suggest to use ansible_python_interpreter=/usr/bin/env python-docker

Playbook 2

We connect to the same host/s again, but now we must use the /usr/bin/env python-docker python interpreter

What is the best way to do this?

Currently we set ansible_python_interpreter on the playbook level of Playbook 2:

---
- name: DaqMon app
  vars:
  - ansible_python_interpreter: "{{ '/usr/bin/env python-docker' }}"

This works, but this will also change the python interpreter of the local actions. And thus the local actions will fail, because (python-docker does not exist locally).

the current workaround is to explicitly specify the ansible_python_interpreter on every local-action which is tedious and error-prone

Questions:

the ideal solution is, if we could add '/usr/bin/env python-docker' as fallback to interpreter-python-fallback - but I think this is not possible
is there a way to set the python interpreter only for the remote hosts - and keep the default for the localhost?
or is it possible to explicitly override the python interpreter for the local host?

回答1:

You should set the ansible_python_interpreter on the host level.

So yes, it's possible to explicitly set the interpreter for localhost in your inventory.

localhost   ansible_connection=local ansible_python_interpreter=/usr/bin/python

And I assume that you could also use set_fact on hostvars[<host>].ansible_python_interpreter on your localhost or docker host.

There is a brillant article about set_fact on hostvars ! ;-P

回答2:

Try to use set_fact for ansible_python_interpreter at host level in the first playbook.

回答3:

Thanks to the other useful answers I found an easy solution:

on the playbook level we set the python interpreter to /usr/bin/env python-docker
then we use a set_fact task to override the interpreter for localhost only
- we must also delegate the facts
- we can use the magic ansible_playbook_python variable, which refers to the python interpreter that was used on the (local) Ansible host to start the playbook: see Ansible docs

Here are the important parts at the start of Playbook 2:

---
- name: Playbook 2
  vars:
  - ansible_python_interpreter: "{{ '/usr/bin/env python-docker' }}"
  ...
  tasks:
  - set_fact:
      ansible_python_interpreter: '{{ ansible_playbook_python }}'
    delegate_to: localhost    
    delegate_facts: true

回答4:

Globally, use the interpreter_python key in the [defaults] section of ansible.cfg

interpreter_python = auto_silent

来源：https://stackoverflow.com/questions/57656073/how-to-set-different-python-interpreters-for-local-and-remote-hosts

标签

ansible

how to set different python interpreters for local and remote hosts