Comment 7 for bug 1979105

Reviewed: https://review.opendev.org/c/starlingx/config-files/+/846454
Committed: https://opendev.org/starlingx/config-files/commit/191e65f85286589bd0529f6dea32046698691b83
Submitter: "Zuul (22348)"
Branch: master

commit 191e65f85286589bd0529f6dea32046698691b83
Author: Robert Church <email address hidden>
Date: Mon Jun 6 03:27:40 2022 -0400

    Debian: Prevent automatic LV event activation

    Historically, with CentOS, we had issues related to LV activation
    occurring in a non-deterministic way and causing an assortment of
    provisioning issues. More deterministic LV activation was achieved by
    setting use_lvmetad = 0 in /etc/lvm/lvm.conf

    In the migration to Debian, a much more recent version of the lvm2
    package is in use. In one of the intervening versions of lvm2, lvmetad
    was removed making use_lvmetad and the associated behavior now obsolete.

    In some current random testing scenarios, emergency mode is seen when
    booting the Debian ISO. Reviewing the systemd dump of services
    initiating when emergency mode occurs, it is observed that LV activation
    is occurring at a different time vs. a successful boot.

    The Debian lvm2 version provides the configuration parameter
    global/event_activation which when set to 0 will change LV activation
    behavior so that when a PV appears pvscan is not called.

    Test Plan:
    PASS - Build ISO, install/provision in AIO-SX virtual/hardware labs
    PASS - Perform numerous reboot cycles an observe no issues
    PASS - Test on H/W setup that has shown emergency mode behavior to
           confirm that this version and associated config file change
           resolved emergency mode PV/LV activation issues

    Test Plan:
    PASS - Build ISO, install/provision in AIO-SX virtual/hardware labs

    Signed-off-by: Robert Church <email address hidden>
    Depends-On: https://review.opendev.org/c/starlingx/integ/+/846453
    Closes-Bug: #1979105
    Change-Id: Ibae56a1da6135ea2f0a1fac76f1ce505a95588f5