Playbook reports different locale depending on control host - ansible

Question

Hello In my playbook I try to determine the locale of the target host using the following command
- name: get locale info
command: printenv LANG
register: my_loc
The strange thing is, the result changes depending on which control host I execute the playbook.
If I run it from my CentOS 8 box i will get as result the value en_US.UTF-8, If I run it a CentOS7 machine I will get en_US.utf8.
These values are the same as i would get in a shell of the console host. But I would expect to that the vales are computed on the target machine and thus should be the same independently from which control host I execute the playbook.
On the CentOS7 machine
[me]$ ansible --version
ansible 2.9.25
config file = /etc/ansible/ansible.cfg
configured module search path = [u'/home/me/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python2.7/site-packages/ansible
executable location = /usr/bin/ansible
python version = 2.7.5 (default, Nov 16 2020, 22:23:17) [GCC 4.8.5 20150623 (Red Hat 4.8.5-44)]
[me]$ printenv LANG
en_US.utf8
On the CentOS8 machine
[me]$ ansible --version
ansible 2.9.25
config file = /home/me/ansible-toolbox/ansible.cfg
configured module search path = ['/home/me/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python3.6/site-packages/ansible
executable location = /usr/bin/ansible
python version = 3.6.8 (default, Sep 21 2021, 20:17:36) [GCC 8.4.1 20200928 (Red Hat 8.4.1-1)]
[me]$ printenv LANG
en_US.UTF-8
The playbook looks like this
# playbook for experiments
---
- name: setup servers
hosts: all
tasks:
# make sure the system local is set to american English
- name: setting up as centos server
command: printenv LANG
register: my_loc
- name: show locale
debug:
var: my_loc.stdout
And I run it with the command
ansible-playbook -i 172.19.1.5 area51.yml
The output is in one case
PLAY [setup servers] *****************************************************************************
TASK [Gathering Facts] ****************************************************************************
ok: [172.19.1.5]
TASK [setting up as centos server] ***************************************************************
changed: [172.19.1.5]
TASK [show locale] ********************************************************************************
ok: [172.19.1.5] => {
"my_loc.stdout": "en_US.UTF-8"
}
PLAY RECAP ****************************************************************************************
172.19.1.5 : ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
And in the other case
PLAY [setup servers] ***************************************************************************************
TASK [Gathering Facts] **************************************************************************************
ok: [172.19.1.5]
TASK [setting up as centos server] *************************************************************************
changed: [172.19.1.5]
TASK [show locale] ******************************************************************************************
ok: [172.19.1.5] => {
"my_loc.stdout": "en_US.utf8"
}
PLAY RECAP **************************************************************************************************
172.19.1.5 : ok=3 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
I have tried the same thing with running the command ssh user#172.19.1.9 printenv LANG and got the same result thus I think it is not a problem with ansible.

Answer 1

The problem her seems to be that ssh transfers the locale settings from the control host to the remote hosts and this will in CentOS have the effect that the remote host will mirror the locale of the control host instead of using the default locale.
See
https://github.com/ansible/ansible/issues/10698