Risk of zombie subprocess when running playbooks in sysinv

[Joshua Kraitberg]

Brief Description
-----------------
A robustness improvement to mitigate the potential of zombie subprocesses in sysinv.

Severity
--------
Minor

Steps to Reproduce
------------------
A number of run_playbook calls are issued within sysinv, such as on sysinv-conductor startup.

Expected Behavior
------------------
No zombie subprocesses

Actual Behavior
----------------
Chance of zombie subprocesses if killed at correct time

Reproducibility
---------------
100% if sysinv is killed while a playbook is running inside a subprocess

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
N/A

Last Pass
---------
N/A

Timestamp/Logs
--------------
N/A

Test Activity
-------------
Developer Testing

Workaround
----------
Use a helper function like subprocess.run or use Popen inside a context manager. "with subprocess.Popen".

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/config/+/859086

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/config/+/859086
Committed: https://opendev.org/starlingx/config/commit/a6b9390179433126192054084f5360f57a27310e
Submitter: "Zuul (22348)"
Branch: master

commit a6b9390179433126192054084f5360f57a27310e
Author: Joshua Kraitberg <email address hidden>
Date: Thu Sep 22 11:21:15 2022 -0400

    Replace unsafe Popen when executing playbooks

    If the sysinv process is killed while a playbook is executing
    in a subprocess that was created with this Popen, it will become
    a zombie.

    By replacing Popen with run, the aforementioned risk is mitigated
    because of the builtin context management and process reaping.

    TEST PLAN
    PASS: Reboot a deployed system (SX/DX), normal operations expected

    Closes-Bug: 1990547
    Signed-off-by: Joshua Kraitberg <email address hidden>
    Change-Id: I1c73ae01e4fa0d61fe774607b7438480470b096c

[Ghada Khalil (gkhalil)]

This code was reverted via this review: https://review.opendev.org/c/starlingx/config/+/861617