Ansible is using wrong version of Python

Question

I have been dealing with this issue for a couple of days now. I am running ansible on a raspberry pi. I have made Python3.7 the default version of Python. Apparently Ansible wants to use Python 2.7. I have added Version 3.7 in the vars in the playbook but this does not change the module location. It still looks for the modules in Python 2.7.

I am not sure how to tell Ansible to use 3.7 for all the modules and the interpreter.

pi@pi:~ $ python --version
Python 3.7.2
pi@pi:~ $ ansible-playbook vm.yaml -vv
ansible-playbook 2.9.6
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/home/pi/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/dist-packages/ansible
  executable location = /usr/bin/ansible-playbook
  python version = 2.7.16 (default, Oct 10 2019, 22:02:15) [GCC 8.3.0]
Using /etc/ansible/ansible.cfg as config file
[WARNING]: provided hosts list is empty, only localhost is available. Note that the implicit localhost does not match 'all'

PLAYBOOK: vm.yaml *************************************************************************************************************************************
1 plays in vm.yaml

PLAY [localhost] **********************************************************************************************************************************************

TASK [Gathering Facts] ****************************************************************************************************************************************
task path: /home/pi/vm.yaml:12
ok: [localhost]
META: ran handlers

TASK [Gather info about the vmware guest vm] ******************************************************************************************************************
task path: /home/pi/vm.yaml:28
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ModuleNotFoundError: No module named 'pyVim'
fatal: [localhost -> localhost]: FAILED! => {"changed": false, "msg": "Failed to import the required Python library (PyVmomi) on pi's Python /usr/bin/python3. Please read module documentation and install in the appropriate location. If the required library is installed, but Ansible is using the wrong Python interpreter, please consult the documentation on ansible_python_interpreter"}

PLAY RECAP ****************************************************************************************************************************************************
localhost                  : ok=1    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0   

pi@pi:~ $ 

Answer 1

To let ansible use the python version other than what it is taking by default, you can use ansible.cfg file inside the project root from where you are running ansible-playbook command.

This file is like a configuration file from which ansible picks up details when it executes a playbook.

Once of its configuration option is interpreter_python where you specify the executable path.

Let's do this step by step :

1. First find the executable path of the python version you would like ansible to use. e.g. if it is python 3.10, you would run which python3.10 from your terminal. It will give you something like /usr/local/bin/python3.10 in the output(which may change if you have it installed in a different directory).
2. Create a file called ansible.cfg in the project root from where you are running your playbooks and add following :

[defaults]
stdout_callback = debug
interpreter_python= /usr/local/bin/python3.10

3. Now when you run the playbooks from this directory, ansible will take the interpreter_python configuration and use python3.10

An important note that now if you run ansible-playbook --version it might still show you the older python version it was using. But when you execute the playbook, it will take the ansible.cfg file into account.