fix: health check incorrectly load inventory sometimes

[auspham]

Description of PR

Summary: Health check sometimes load wrong inventory admin/password
Fixes # (issue) 36307349

From investigating I can see that this issue sometimes happen, sometimes doesn't happen. Diving deeper, I can see that this is heavily dependent on how Ansible process and use memory internally.

This would only happen if there are 2 fanout hosts. One is using sonic and one is using non-sonic

In a happy scenarios, comparing the fanouthost.vm.extra_vars of 2 fanouts, we can see that they have different memory address

memory id 140619746693120 host XXXX <----- DIFFERENT ID HERE

2026-01-08 11:31:14,402 testbed_health_check.py#185 INFO - {'hostname': 'XXXX', 'reachable': True, 'failed': True, 'module_stdout': '', 'module_stderr': '/bin/sh: /usr/bin/python3: No such file or directory\n', 'msg': 'The module failed to execute correctly, you probably need to set the interpreter.\nSee stdout/stderr for the exact error', 'rc': 127, 'ansible_facts': {'discovered_interpreter_python': '/usr/bin/python3'}, '_ansible_no_log': False, 'changed': False}

memory id 140619740737472 host YYYY  <----- DIFFERENT ID HERE

2026-01-08 11:31:15,404 testbed_health_check.py#185 INFO - {'hostname': 'YYYY', 'reachable': True, 'failed': False, 'ping': 'pong', 'invocation': {'module_args': {'data': 'pong'}}, 'ansible_facts': {'discovered_interpreter_python': '/usr/bin/python3.9'}, '_ansible_no_log': False, 'changed': False}

In some scenarios, however, if ansible decided to re-use the memory address when initialising its VariableManager, we have the issue happen

memory id 139728659566400 host XXXX <---- SAME ID HERE

2026-01-08 11:31:43,750 testbed_health_check.py#185 INFO - {'hostname': 'XXXX', 'reachable': True, 'failed': False, 'ping': 'pong', 'invocation': {'module_args': {'data': 'pong'}}, 'ansible_facts': {'discovered_interpreter_python': '/usr/bin/python3.9'}, '_ansible_no_log': False, 'changed': False}

memory id 139728659566400 host YYYY <---- SAME ID HERE

2026-01-08 11:31:44,384 testbed_health_check.py#185 INFO - {'hostname': 'YYYY', 'reachable': False, 'failed': True, 'unreachable': True, 'msg': "Invalid/incorrect password: Warning: Permanently added '10.150.22.30' (ED25519) to the list of known hosts.\r\nNOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE\n\nUnauthorized access and/or use prohibited. All access and/or use subject to monitoring.\n\nNOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE\nPermission denied, please try again.", 'changed': False}

Since we're overwriting the ansible_ssh_user and ansible_ssh_password in the extra_vars

fanouthost.vm.extra_vars.update({"ansible_ssh_user": fanout_sonic_user, "ansible_ssh_password": fanout_sonic_password})

If in the scenario that the two memory addresses are the same, it will overwrite the ansible_ssh_user, and ansible_ssh_password as well. And everything in extra_vars takes top priority over inventory defined variables.

Therefore it leads to using wrong username and password.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• New Test case
  • Skipped for non-supported platforms
• Test case improvement

Back port request

• 202205
• 202305
• 202311
• 202405
• 202411
• 202505
• 202511

Approach

What is the motivation for this PR?

How did you do it?

How did you verify/test it?

Any platform specific information?

Supported testbed topology if it's a new test case?

Documentation

[mssonicbld]

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